The unheralded Belgian started brightly and held firm to take the opening set in a tense tie breaker.
Nadal kept fighting despite visible discomfort with a persistent knee injury, dropping the second set in a marathon breaker that saw both players spurn chances in an entertaining exchange.
Darcis showed composure belying his ranking to close out the match in straight sets, beating the two-time Wimbledon champion 7-6(4) 7-6(8) 6-4.
Look back at the shock result from the opening day at SW19 with Sports Mole's minute-by-minute text commentary below.
2.53pmAfternoon eager Wimbledon fans. Thanks for joining Sports Mole as Rafael Nadal begins his quest for a third title at SW19 with a first-round match against Steve Darcis.
2.56pmNadal has been in awesome form since returning from a career-threatening knee injury, but will need to shake off some rust today in his first match on grass this season. All eyes will be on the Spaniard this afternoon as he looks to adjust to the quick surface with minimum fuss.
2.59pmThat seventh month absence means that Nadal enters Wimbledon as fifth seed in the men's singles, his lowest seeding since 2002. The draw has thrown up a potential quarter-final between traditional Wimbledon rivals Nadal and Roger Federer, but there is a full week of tennis to get through first for both players.
3.01pmBoth players are just about ready to come out on court one, which means play should get underway in about five minutes time. Nadal as expected gets a very warm reception, in his first showing at Wimbledon since that shock defeat to Lukas Rosol in the second round last year.
3.04pmA quick word on Nadal's opponent this afternoon and a big occasion for 29-year-old Steve Darcis. The Belgian number four has been ranked in the top 50 during the early part of his career, but has since slumped to 135. The two players have met just once before, with Darcis forced to retire with a back injury in Doha three years ago.
3.07pmAs both players put the finishing touches to their warm-up let's take a closer look at Nadal's remarkable return to top form this season. In 45 matches on the tour in 2013 the Spaniard has lost just twice, reaching at least the final in each event he has entered. Considering the questions marks over his future in the sport that is a quite incredible record, making Darcis's task look particularly daunting today.
3.09pmPre-match formalities are at end and we are about to get underway. Nadal will serve first at the bottom of the court, after taking his time to complete a compulsive routine.
3.11pmBREAK POINT! A little slip during the second point for Nadal at the baseline, with Darcis taking advantage to level at 30-30 with a clever backhand slice. Break point soon follows for the Belgian, what a chance this is even so early in the match.
3.14pmDarcis spurns two consecutive chances to break after a rare Nadal double fault, with his attempt at a slice winner down the line just drifting a few inches wide. Nadal then mixes things up by charging in from the net, smashing a fierce winner at the net to reach game point.
Nadal 1-0* DarcisAfter a rusty start Nadal saves two break points to hold thanks to an unforced error from Darcis. We expected a slightly slow opening from the fifth seed given his two-week break, but as usual the Spaniard finds a way to hold under early pressure.
Nadal *1-1 DarcisA composed, routine hold for Darcis in his first service game, which bodes well for a competitive first-round match. The Belgian showed nice variety on serve and looks very strong on his forehand side early in this first set.
3.20pmAn early contender for shot of the match from Darcis, who punishes Nadal for a short pass by sending a crisp backhand winner down the line.
3.22pmThe crowd at court one are quickly applauding the world 135 again for shot showcasing superb technique, as Darcis aims a wonderful backhand across court and inside the line. Inconsistency then lets the Belgian down with his next shot, but a rare Nadal error then hands the underdog break point.
Nadal 2-1* DarcisNadal smacks an ace right down the line to fight back at deuce, with Darcis buckling in a long rally in the next point. A forceful backhand across court does the job for Nadal at game point, closing out a hold that saw the Spaniard save his third break point of the match even at this early stage.
3.28pmThe two-time Wimbledon champion is starting to settle as he sends a trademark forehand winner right down the line to level at 30-30. Darcis stays strong with a textbook serve-volley in the next point, but an unforced error quickly takes his second service game to deuce.
Nadal *2-2 DarcisMore confident play on serve helps Darcis level the match early in the first set, with the Belgian quick to take his chance at the net after a strong first serve. You sense that Nadal is just easing into the tournament here, giving Darcis the chance to build some confidence with some efficient shot selection.
3.32pmBREAK POINTS! A quite sensational backhand from Darcis earns the Belgian three more break points at 0-40. Surely he has to take this chance to harbour any realistic hopes of taking this first set!
3.34pmIn the blink of an eye that Darcis has the door shut firmly in his face chasing a break of serve. Nadal follows up a strong first serve with some clever approach play at the net, rattling off four points in quick succession to get the advantage back on serve.
Nadal 3-2* DarcisWell another battle of wills on the Nadal serve sees Darcis spurn his sixth break-point chance, thanks primarily to a consistent string of first serves from the Spaniard. Against a player of Nadal's calibre you simply have to take those chances when they come, but there is still plenty to admire about a positive start on court one from the world number 135.
3.41pmDarcis edges a marathon rally at the start of his third service game, that point must have lasted at least 15 strokes. At 40-15 the Belgian makes an error with a volley at the net, with Nadal capitalising to force deuce with a strong forehand aimed low at the baseline.
Nadal *3-3 DarcisA nice show of stubborn resistance from Darcis, who holds off a break point with a fierce first serve. A tight, gruelling game reaches its fifth deuce before Darcis makes a breakthrough with an overhand smash, with more serve and volley enough to earn a hard-fought hold.
3.48pmYou feel that Nadal is starting to thrive in the competitive atmosphere of this first set, with the Spaniard easing into a 30-15 lead on serve. A quite awesome backhand into the far corner then helps Darcis draw level at 30-30, with the Belgian slightly fortunate to take the point as his volley at the net bounces in off the frame of his racket.
3.51pmBREAK POINT! Another beautiful backhand down the line earns Darics his eighth chance to break, but once again Nadal recovers by mixing things up with a forehand deep at the baseline.
Nadal 4-3* DarcisA thoroughly entertaining first set continues as Nadal edges a quality exchange of volleys at the net, with a brave dive from Darcis not enough to stop Nadal taking his fourth service game. The crowd on court one are really enjoying this first set, with Nadal being matched all the way by the Belgian underdog.
Nadal *4-4 DarcisThe world number 135 continues to show surprising variety and composure on serve, quickly producing the first hold to love of the match. We are fast approaching the business end of this first set, can Darcis continue to push Nadal when the pressure heightens?
Nadal 5-4* DarcisA few early unforced errors from Nadal continue to be outweighed by his class under pressure, with a sublime backhand bouncing off the line to keep this tight first set on serve. Darcis will serve next to stay in the set, but has has shown no signs of buckling so far with a mix of power and guile.
4.00pmA precise forehand winner helps Darcis ease into this important game, with the Belgian building a 30-15 lead with his fifth ace of the match.
Nadal *5-5 DarcisUnder pressure that was a terrific effort from Darcis, who is not afraid to come in at the net and shorten his points on serve. Nadal looks slightly taken aback by his opponent's efforts as he loses the opening points of his next service game.
4.05pmBREAK POINTS! Two rare unforced errors have handed Darcis a pair of break points. He really must take these surely!
Nadal 5-6* DarcisBREAK! After eight failed efforts Darcis finally gets the breakthrough his positive start has merited. Nadal looked slightly lethargic as he failed to chase down a forehand, with the shot proving enough to help the Belgian take a 6-5 lead, with Darcis now about to serve to take the opening set.
4.08pmBREAK POINT! A well-placed smash from Darcis brings this vital game to 15-15, with a risky forehand side handing Nadal a cheap point straight after that effort. A fearsome forehand up the line sees Nadal seize the initiative, with two break points quickly brought up for the Spaniard.
Nadal *6-6 DarcisBREAK! Darcis saves the first break point with an ace awarded by hawkeye, but Nadal quickly takes his next chance to earn a break back, forcing this first set to a tie break.
4.12pmNadal punishes an early mistake in the breaker from Darcis, sending a strong forehand pass across court to level things up at 1-1.
4.13pmAce number seven keeps Darcis ahead in tie-break on serve, with Nadal slipping 3-1 behind after an uncharacteristic double fault.
4.15pmA pair of unforced errors from Darcis levels the breaker at 3-3 at the change of ends, with Nadal looking determined to claim this first set. Darcis must keep up the pressure and force his more experienced opponent into mistakes, which he has done with alarming regularity in the first hour of this match.
4.17pmDarcis takes a chance at the net and gets a quick reward, smashing to go 4-3 up. On the Nadal serve another high smash from the Belgian is timed to perfection, earning a mini-break and a 5-3 advantage in this tense breaker.
4.18pmSET POINTS! Another wonderful forehand into the corner from Darcis brings up three set points he fully merits, with Nadal unable to keep a deep forehand pass in at the baseline.
Nadal 6-7(4)* DarcisSET! More inventive play sees the world number 135 take the first set in quite stunning fashion. Nadal is left chasing a volley at the net in vain and concedes the first set to the Belgian underdog. Do we have a major upset brewing on court one this afternoon?
4.22pmYou have to say the Darcis deserved to claim that first set, with a mix of strong serving and brilliant backhand winners forcing Nadal into rare mistakes at the baseline. The Spaniard's response early in the second set will be vital, but you would expect the fifth seed to react positively under pressure.
Nadal *6-7(4) 0-1 DarcisA very surprising high standard of tennis continues from Darcis, who takes a comfortable hold to star the second set. Nadal needs to react strongly with his next service game, but definitely looks a little rattled by the strong shot making of his opponent.
4.27pmDarcis takes two early points with strong returns and has an early sight of a break in this second set. Nadal fights back and benefits from a pair of unforced errors to level up at 30-30, with the first audible cries of Vamos coming from the Spaniard, primarily from sheer relief surely.
Nadal 6-7(4) 1-1* DarcisRafa regroups to secure a hold he desperately needed, giving him a platform to build on early in this second set.
4.29pmBREAK POINT! A fine run of forehand winners finally ends for Darcis, with Nadal forcing his opponent back at the baseline and following up to make it 30-30 on the Belgian's serve. A forehand volley at the net then proves enough to earn the Spaniard a welcome break point early in this second set.
Nadal 6-7(4) *1-2 DarcisNadal lets a chance slip to aim a wrap-around forehand winner, delaying a shot that came crashing back off the wooden frame of the net. Darcis then recovers to claim advantage thanks to an unforced error from the fifth seed, following up with a well-time ace to earn a terrific hold.
4.35pmAnother cheap error at the baseline from Nadal sees him go 0-30 down on serve, with the Spaniard escaping in the next points as Darcis just sends a backhand volley wide at the net.
Nadal 6-7(4) 2-2* DarcisUnder pressure Nadal responds magnificently, winning four successive points to claim a much-needed hold. The Spaniard still looks unsettled and is being made to chase hard for every point by Darcis, who looks determined to keep this high pace up in the second set.
Nadal 6-7(4) *2-3 DarcisThe Belgian is showing no signs of letting up, slamming a fierce serve down the line for a routine hold to love. This is just Darcis's ninth match on tour this year, making his impressive display on court one all the more surprising against a former two-time Wimbledon champion.
Nadal 6-7(4) 3-3* DarcisDarcis challenges a call after Nadal sends a bullet down the line, with Hawkeye confirming that the ball was definitely in. The Spaniard uses that momentum to claim his first hold to love, with the points in this second set getting noticeably shorter as the pace falls off for both players.
4.44pmNadal slams a very strange forehand into the net as he tried to chase down a slow second serve from Darcis, allowing the Belgian to build a 40-15 lead on serve.
Nadal 6-7(4) *3-4 DarcisWithout wishing to worry Nadal fans he definitely looked to be keeping the weight off his left knee in that last game, with Darcis able to maintain momentum and edge back ahead on serve in the second set.
4.48pmA blistering forehand from Nadal bounces right on the line, a purely instinctive winner that has Darcis beaten all ends up. The Belgian once again shows character to win the very next point, with the score finely poised at 40-30 on the Spaniard's serve.
Nadal 6-7(4) 4-4* DarcisA loud cry of Vamos from Nadal as he crashes a fifth ace down the line, keeping this second set on serve in the process.
Nadal 6-7(4) *4-5 DarcisMore high-risk play from Darcis pays off as forehand winner flies inside the line to perfection. The Belgian then sends a huge ace across court for an easy hold. There is still no sign of the world number 135 slowing down, with a bemused Nadal now forced to serve to stay in the second set.
4.55pmDarcis gets the better of a gritty baseline exchange at the start of this crucial game, uncorking a massive forehand to catch Nadal on his heels at the baseline.
Nadal 6-7(4) 5-5* DarcisA cheap unforced error from Darcis lets Nadal off the hook at 30-30, with the Spaniard taking full advantage with a soft volley slowing up to perfection at the net. That hold showed Nadal's famous fighting spirit, but there is still plenty of work to do here for the fifth seed.
4.49pmFinally some signs of strain from Darcis, with two poor shots at the baseline helping Nadal take a 0-30 lead on the Belgian's serve. This is a huge chance for a first break in the set for Nadal!
Nadal 6-7(4) *6-5 DarcisBREAK! A smash from Darcis slams into the net, handing Nadal a timely break that he greets with a fierce fist pump. Despite a severe test in the last two hours Nadal will now serve for the second set, with an opportunity to level the match despite appearing to be in a bit of discomfort.
5.05pmA curious start to the game sees Nadal get a challenge all wrong at the baseline, before swiftly sending a forehand winner long to go 0-30 down on serve.
5.07pmBREAK POINTS! With precision Darcis earns a pair of chances to instantly break back. What a moment this could be in the context of the match, with Nadal under pressure on serve with the second set in his sights.
Nadal 6-7(4) 6-6* DarcisBREAK! The disbelief on court one continues as Nadal crashes a stray forehand into the net, giving Darcis the break he needed to force this second set into a tiebreak. What an effort from the unheralded Belgian as this match enters its third hour.
5.10pmThe standard of play is very high in this first two points of the tiebreak, but on both occassions Darcis prevails in long rallies to build a 2-0 lead. Nadal then responds to reduce the deficit at the net, with the Belgian's loose double fault bringing the two players level once more.
5.12pmDarcis builds a 4-2 lead in this breaker at the change of ends, with yet another unforced Nadal error ending a marathon rally at the baseline.
5.14pmNadal benefits from a poor call from the line judge, with a successful challenge from Darcis allowing the Spaniard to replay a point he could have easily lost with a first serve. Darcis shows terrific character to respond under pressure, keeping his mini-break intact with a 5-3 advantage.
5.15pmSET POINTS! A massive 121mph serve hands Darcis three set points, with Nadal's attempt to challenge the call in vain. What a moment for the Belgian, with Nadal saving the first effort to make the breaker 6-4.
5.18pmA Nadal looks destined to float long but somehow bounces inside the line, with Darcis caught completely by surprise to send a stray forehand well wide. That miscue sees the Belgian's third set point go begging, with this pivotal breaker all square at 6-6.
5.20pmA fourth set point evades Darcis, with Nadal taking a chance at the net and forcing a mistake in the process. This tie-break is still very much there for the taking at 7-7.
5.22pmThis time with his first set point Nadal is the one who buckles, sending a tame slice into the net. Darcis is quick to capitalise with a massive serve down the middle, earning his fifth set point in the process at 9-8 in the breaker.
Nadal *6-7(4) 6-7(8) DarcisSET! Quite amazingly Darcis has built a two-set lead in this first-round match, with Nadal forcing a forehand long to lose a marathon breaker. The Belgian looks remarkably calm as he sits down ahead of the third set, can he maintain this high standard of play to close out easily the biggest win of his career?
5.28pmNadal has come from two-sets down before at Wimbledon and will need to repeat that feat to avoid a massive upset this afternoon. The Spaniard has never lost in the first round of a Grand Slam, but is immediately under pressure in this third set on serve.
5.30pmBREAK POINTS! A pair of tame second serves from Nadal are punished as he goes 15-30 down. Darcis then forces Nadal to chase down a high volley at the net, but the Spaniard's knee clearly buckles as he falls 15-40 behind. Two break points here for Darcis early in the third set!
Nadal 6-7(4) 6-7(8) 0-1* DarcisBREAK! Composure and quality once more from the world number 135, with Darcis claiming a vital break with a forehand winner than sends Nadal the wrong way. Has Nadal got enough left in the tank to respond? You can never count out the eight-time French Open winner, but he clearly looks to be bothered by his left knee when extending to reach the ball.
5.32pmA pair of untimely double faults from Darcis give his opponent a glimmer of hope as he looks for an instant response, but Darcis somehow responds magnificently to curl a backhand winner up the line to make the score 30-30.
Nadal 6-7(4) 6-7(8) *0-2 DarcisI don't think there is any question now that Nadal is struggling physically to chase down these Darcis cannons across court, with the Belgian taking advantage to earn a hard-fought hold. If the Spaniard harbours any realistic hopes of a comeback he surely must hold in the next service game.
Nadal 6-7(4) 6-7(8) 1-2* DarcisA very welcome hold to love for Nadal, with Darcis now perhaps showing signs of fatigue for the first time. Quite surprisingly Nadal has yet to call for the trainer, with the Spaniard determined to press on and keep fighting at two sets down.
5.40pmTwo unforced errors on his forehand sides let a bright start to the game slip for Darcis at 30-30, but with the pressure on a precise first serve keeps the Belgian ahead.
Nadal 6-7(4) 6-7(8) *1-3 DarcisNadal decides to stay off his backhand side and pays a heavy price, allowing Darcis time to pick his shot and stay a break up in the third. How the Spaniard must be yearning for the forgiving clay of Roland Garros at this juncture.
5.43pmNice variety at the net helps Nadal build a 30-0 lead on serve. Perhaps the fifth seed should look to shorten points like that at every opportunity, particularly to avoid a painful chase at the baseline with his knee in discomfort.
Nadal 6-7(4) 6-7(8) 2-3* DarcisA second successive hold to love keeps Nadal alive in this third set, but he still trails by that early break. It must be said that Darcis looks very composed under pressure he has probably never experienced, but has ice on his thigh in a break between games. Maybe a glimmer of hope for Nadal there if that muscle proves to be problematic late in the match.
5.47pmNadal is clearly struggling to apply pressure on his backhand shots, helping Darcis win two quick points on serve.
Nadal 6-7(4) 6-7(8) *2-4 DarcisA backhand slice helps Darcis move to within two games of a straight-sets win over the two-time Wimbledon champion, quite incredible. Nadal was noticeably unable to chase down two shots in that last game, but continues to press on without asking for medical assistance.
Nadal 6-7(4) 6-7(8) 3-4* DarcisUnsurprisingly Nadal shows the character of a champion to keep fighting, claiming a comfortable hold to just about stay in touch. All the pressure is now definitely on Darcis, can he maintain what has been nothing short of exemplary form to claim a massive upset victory?
5.53pmNadal is caught on his heels by an instinctive shot at the net by Darcis, who follows up with a pinpoint volley to edge 15-30 ahead on the Spaniard's serve.
5.55pmMore bravery from Nadal sees this service game for Darcis head to deuce, with a lengthy baseline exchange helping the Belgian claim game point after a misplaced Nadal forehand.
Nadal 6-7(4) 6-7(8) *3-5 DarcisNadal must now serve to stay in the match as Darcis shows composure to close out a tight service hold. All or nothing now for the fifth seed, who starts on serve by missing what looks to be a routine volley at the net.
6.00pmAnother unforced error from Nadal sees the Spaniard caught by surprise at the baseline, allowing Darcis to draw level at 30-30.
Nadal 6-7(4) 6-7(8) 4-5* DarcisA gutsy effort from Darcis sees his attempt at risky forehand winner bounce just beyond the line, with a long forehand in the next point helping Nadal hang in there with an imperative hold. The Belgian will now serve for the match after just over three hours of superb play in all areas of the game.
6.02pmNadal jumps out of his chair defiantly ahead of this vital game and makes an improbable backhand winner down the line under pressure. A huge shout of vamos from the fifth seed, with Darcis responding in kind to level at 15-15. You can feel the tension now on court one.
6.04pmMATCH POINTS! An amazing effort from Darcis sees him somehow chase down a volley at the net, scrambling a forehand over to edge 30-15 ahead. The Belgian is pumped up with that one and quickly forces an error to claim two match points.
Nadal 6-7(4) 6-7(8) 4-6 DarcisGAME SET AND MATCH! A massive ace completes the match of Steve Darcis's life. He beats a struggling Nadal in straight sets, condemning the Spaniard to defeat in his opening match at a Grand Slam for the first time in his career.
6.07pmBoth men get the standing ovation their efforts deserve from a delighted crowd on court one, with Darcis in dreamland as he laps up a prolonged applause. The world number 135 has only played nine matches on the full tour this season, and despite Nadal's injury troubles you can take nothing away from the 29-year-old's awesome display this afternoon.
6.09pmWhat a shock to start Wimbledon 2013. That win for Darcis opens up the men's draw nicely and serves as a reminder that anything can happen at this tournament. Darcis deserves all the plaudits that will come his way, after easily the best performance of his career today. Lukas Rosol eat your heart out!
6.12pmThat just about does it for coverage of a memorable first round match at SW19. Thanks for your time and be sure to stick with Sports Mole for comprehensive Wimbledon coverage over the next two weeks. Good afternoon.