It was Janowicz who edged ahead in a brutal first set, using a fierce first serve to ease clear of the veteran Kubot in the early stages.
Just one break of serve was enough in all three sets for Janowicz, with the 22-year-old serving 30 aces in a straight-sets victory.
Look back at a momentous win for the young Pole with Sports Mole's minute-by-minute commentary below.
3.42pmAfternoon Wimbledon fans. Sports Mole's comprehensive coverage from SW19 continues with a surprise men's quarter-final featuring Polish Davis Cup teammates, with Jerzy Janowicz taking on Lukasz Kubot.
3.44pmThis is without the doubt the biggest match of both players' careers, and perhaps the most important in Polish men's tennis history. Janowicz goes into the clash as favourite after entering the world's top 20 for the first time this year, but Kubot is definitely a live danger.
3.46pmJanowicz has taken some notable scalps on his way to the last eight, earning straight-sets wins over Nicolas Almagro and Jurgen Melzer. Kubot has showed superb spirit to defy the odds and reach this stage, and can surely go into his first appearance on Court One with nothing to lose.
3.49pmI expect some nerves from both players in the early going given their lack of experience at this level. It will be very interesting to see who seizes what is a unique opportunity to reach a Grand Slam semi-final without facing a top seed. Surely these two close friends will give everything for victory this afternoon, but I think Janowicz's formidable serve might well make the difference.
3.52pmHere we go then, with world number 130 Kubot to serve first. He immediately drives to the net in his opening point and the move pays off, with Janowicz driving an ambitious forehand wide.
Janowicz *0-1 KubotA routine hold to ease any early nerves for Kubot. You can see from the Polish number three's first service game that he has a game firmly rooted in fine touch at the net, which is no surprise given that he is a regular on the doubles scene.
Janowicz 1-1* KubotJanowicz warms up with a massive 140mph serve, by my reckoning the joint-quickest serve of the tournament. He swiftly follows that with a wide ace and a 137mph drive up the middle. Fearsome stuff there for a hold to love in under a minute.
Janowicz *1-2 KubotSharp movement at the net from Kubot moves him 30-0 up on serve, but a fierce forehand return from Janowicz in the next point just lands inside the baseline to reduce the deficit. The 31-year-old remains unfazed and keeps wide on serve to get a hold that saw him concede just a single point.
3.59pmDespite being Davis Cup colleagues these two friends could hardly possess more contrasting games. Kubot makes an aggressive move on second serve but another dart to the net proves futile on this occasion, with a volley falling short at 30-15. A double fault soon follows though from Janowicz to make this service game competitive.
Janowicz 2-2* KubotDespite serving two double faults Janowicz gets a second hold, which must feel good as Kubot fails to take advantage of those errors. No sign so far of nerves from the two players in baseline exchanges as Court One finally begins to fill up.
Janowicz *2-3 KubotStill on serve as Kubot keeps providing neat touch to deny Janowic chances to unleash power from deep at the baseline. The world number 130 needs to maintain this high-energy approach in the match of his life and has made a confident start.
Janowicz 3-3* KubotA 134mph serve brings up another hold to love for Janowicz, who clearly wants to move between points and games with breakneck speed when possible.
4.08pmKubot is clearly prepared to gamble on serve and steps inside with aggression, but on successive points his volley drifts wide to level a tight service game at 30-30.
Janowicz *3-4 KubotUnder pressure Kubot finds a first ace down the middle, following that fine effort up with a deep forehand into the corner. Janowicz definitely failed to seize that chance, deciding to stay deep at the baseline and ease his way into the match.
Janowicz 4-4* KubotJust one point earned against Janowicz's serve in open play so far, with another procession keeping this first set deadlocked. Time for one of these two unheralded quarter-finalists to make a move and wrestle control of the match.
Janowicz *4-5KubotI've been a little disappointed with Janowicz on return so far this afternoon, with Kubot slamming a superb first serve down the middle. These service games are being swatted aside at a serious pace, with nine successive holds in just 24 minutes.
4.19pmFinally some signs of pressure on the Janowicz serve as Kubot picks up two cheap points to level at 30-30. The 22-year-old responds strongly with a forehand winner up the line, but a double fault after going too big with a second serve ties things up once more at deuce.
4.21pmSET POINT! Kubot places a superb return deep at the baseline after reading a 133mph serve, earning a single set point in the process.
Janowicz 5-5* KubotBy far the longest rally of the match sees Janowicz stay composed to level at deuce, finding depth behind a clean forehand winner into space. The 22-year-old follows that up with a wide 137mph ace to edge ahead, finishing the job with a backhand pass down the line.
4.24pmBREAK POINTS! That trouble on serve looks to have given Janowicz a lift as he earns two break points with minimum fuss, exposing a late movement to the net from Kubot.
4.27pmBREAK POINT! Kubot is hanging tough on serve, saving three break points as he makes a wide second serve work to his advantage. Another risky volley at the net drifts just past the line in the next point, giving Janowicz a fourth break-point chance.
Janowicz *6-5 KubotBREAK! A huge roar from Janowicz as a deep forehand return at the baseline pays off, earning a vital break at the fourth time of asking. The giant Polish number one will now serve for the first set as Kubot just gets a touch too predictable at the net.
4.30pmAn absolute rocket serve up the middle from Janowicz goes unreturned, but a swift double fault soon after give Kubot a glimmer of hope at 30-15.
Janowicz 7-5* KubotSET! Ace number 10 earns the 22-year-old two set points, with a wide effort getting the job done. First blood to Janowicz as he goes a set ahead after 40 minutes.
4.35pmImportant for Kubot to build bridges quickly after that setback as he serves to start the second set. His touch at the net has just deserted him in the last few games, with Janowicz stepping things up a touch with power at the baseline.
Janowicz 7-5 *0-1 KubotA fine effort there from Kubot to hold serve, reverting to a wide slice serve that definitely packs a punch, just not compared to his 6 foot 8 opponent.
4.38pmUPDATE! News of a bad start for Andy Murray on Centre Court. The second seed has dropped the opening set to Fernando Verdasco 6-4 for his first blemish of the Championship.
Janowicz 7-5 1-1* KubotBrute force on serve helps Janowicz hold to love inside a minute. Tough to live with the sheer power of that first serve for any player when the 22-year-old finds range and depth with regularity.
4.41pmBack to serve volley for Kubot and initially it pays off, helping the world number 130 build a 40-30 lead. Janowicz then shows surprising pace to force deuce, chasing drop a short drop shot with relative ease.
Janowicz 7-5 *1-2 KubotA hard-fought hold there for Kubot as he finds accuracy just when it matters on first serve. Janowicz is really starting to find his stride at the baseline though, which is slightly worrying for the 31-year-old.
4.44pmBREAK POINTS! Quick reactions help Kubot build a 15-30 lead and a chance to put the Janowicz serve under rare pressure. The 22-year-old then sends a slack slice in the net, handing his opponent two break points.
Janowicz 7-5 2-2* KubotWell under the cosh Janowicz has just produced a supreme show on serve, winning four successive points that included a pair of timely aces. Kubot really went for that game in a bold display, but ultimately just could not sustain the momentum to earn a break he desperately needs.
4.51pmMore consistent serve and volley helps Kubot go 40-15 up serve, but that work in undermined by a double fault well past the line. The 31-year-old then slams a slack volley short of the net, levelling a crucial game at deuce.
Janowicz 7-5 *2-3 KubotA spirited show of resistance from Kubot there on serve, hanging tough and showing neat touch to get his tall opponent off balance and keep the second set on serve. But only just!
4.55pmBREAK POINT! Janowicz has called for the trainer before starting his latest service game, complaining of pain in his right arm. Kubot takes advantage quickly, edging ahead after a long rally to go 30-40 up at break point.
Janowicz 7-5 3-3* KubotA sixth double fault puts all the pressure on Janowicz and hands his opponent a second break point. Once again the veteran is unable to take advantage, slamming a sloppy forehand short at the net to let Janowicz off the hook. A subtle serve then gets the job done for the Polish number one, who has now saved six break points in this match.
5.00pmJanowicz absolutely slams a backhand return down the line to go 0-30 ahead on the Kubot serve. After letting a chance slip through his grasp in the last service game Kubot must now dig deep and responds strongly, chasing down a drop set with ease at the net.
5.02pmBREAK POINTS! Janowicz ruthlessly exposes a short volley with a fine forehand pass, earning two break points at 15-40 in the process.
Janowicz 7-5 *4-3 KubotBREAK! Once again Janowicz is able to build momentum after saving break-point chances. Precise shots at either side of the court prove too strong for Kubot, who is now staring down the barrel of a two-set deficit.
5.05pmA quick moment between change of ends for Janowicz to take what seems to be sugar tablets issued by the trainer. The crowd are busy purring at a surprise scoreline from Centre Court, which we will bring you news of in just a moment.
5.07pmUPDATE! The big news from centre that momentarily got the crowd worked up over here as Janwociz attempted to serve. Andy Murray is 5-3 down in the second set to Fernando Verdasco, who is serving for a shock two-set lead.
Janowicz 7-5 5-3* KubotWhat a time to produce a love service game for Janowicz, piling the pressure on his countrymen who must now serve for his place in the second set.
Janowicz 7-5 *5-4 KubotCertainly no signs of a drop in effort form Kubot, using touch and guile at the net to hold in a high-quality service game. Janowicz took it a little easy there and will now concentrate his efforts on serving for the second set.
Janowicz 7-5 6-4* KubotSET! Barely time for Kubot to take a breath let alone build pressure in a crucial game, falling two sets behind after a hold to love. The 22-year-old is now in complete control of the match thanks that ferocious first serve and some gutsy play at break-point down.
5.14pmUPDATE! Bad news to report from Centre Court for British tennis fans. Andy Murray has fallen two sets behind against Fernando Verdasco, and now faces an uphill task to keep home interest in the tournament alive.
5.17pmSpeaking of uphill battles back on Court One Kubot is struggling slightly to keep his second serve in play now. Janowicz looks primed and ready to take advantage, with the opening game of the third set locked at 30-30.
5.19pmBREAK POINT! Staring at another setback Kubot goes for broke on second serve. Fresh from a third double fault his bold move pays off, swatting a sweet volley aside to level at deuce.
Janowicz 7-5 6-4 *0-1 KubotStrong stuff under pressure from Kubot, with Janowicz stubbornly refusing to try the lob and getting caught in the process. The challenge for Kubot now in this third set is to finally take a break point, with six chances spurned so far today.
Janowicz 7-5 6-4 1-1* KubotMore routine fare for Janowicz on serve, crashing a ferocious 135mph effort down the line for his 23rd ace and a quick hold. If the 22-year-old can maintain that standard surely his first Grand Slam semi-final awaits.
5.25pmBREAK POINT! At the worst possible time Kubot's touch at the net disappears, gifting Janowicz two break points and a 15-40 lead on his opponent's serve. A break here could prove potentially decisive.
Janowicz 7-5 6-4 *1-2 KubotWith his back against the wall Kubot delivers his best tennis of the match. Guided by that trusty wide serve the veteran wins four successive points, holding to ease back ahead early in the third set.
5.29pmTime for new balls on the Janowicz and after a sluggish first effort he finds range, with his service game deadlocked at 30-30. For the first time there are visible signs that the 22-year-old is struggling with that arm injury he complained of during the second set.
5.32pmBREAK POINT! Aggression at the net from Kubot keeps a tight Janowicz service game at deuce. Both players look a touch tense in the third set but it's Kubot who reacts quickest on serve, driving inside to earn another break-point chance.
Janowicz 7-5 6-4 2-2* KubotA huge hold for Janowicz there as he clings on to survive once more at break point. Aged just 22 the way he responds is a credit to the Polish number one, but surely Kubot will rue missed chances in the biggest match of his career.
Janowicz 7-5 6-4 *2-3 KubotNo signs of Kubot growing disheartened as he holds to love, recovering quickly form a slip at the baseline to win four successive points.
5.40pmThe battle between baseline bruiser and netplay continues to go Janowicz's way, with an awesome baseline winner helping the youngster build a 30-0 lead on serve.
Janowicz 7-5 6-4 3-3* KubotAnother routine hold built behind big-serving for Janowicz keeps the third set on serve. Kubot shows glimpses of ability but cannot close out a break of serve, and that must change quickly or his tournament will be over today.
Janowicz 7-5 6-4 *3-4 KubotMake that ten successive points on serve for Kubot as he wraps up a comfortable hold under little pressure. The 31-year-old is now back ahead in the third set, still fighting hard for every point which must be considered a positive sign.
5.48pmGreat length on successive returns helps Kubot put pressure on his opponent's huge serve, nudging 15-30 ahead as a result. Janowicz slams a 138mph serve down the middle to quickly level, with a a massive forehand down the line easing him ahead soon after.
Janowicz 7-5 6-4 4-4* KubotA double fault puts the Janowicz under pressure at deuce, but he responds with another quite brilliant slice serve down the middle. No sign of a breakthrough yet in the third set as we head quickly towards crunch time.
5.53pmBREAK POINTS! Massive pressure on Kubot as a string of unforced errors quickly see him fall 0-40 down in a crucial service game.
5.56pmBREAK POINT! A magnificent effort there from Kubot, saving three break points as he goes for broke at the net. He can't sustain that strong effort though, getting poor contact on a backhand volley to gift Janowicz a fourth break point.
Janowicz 7-5 6-4 *5-4 KubotBREAK! What a time to use your first lob of the match. A clever, calculated risk from Janowicz pays off big time, with Kubot left wanting with a forehand pass towards the sideline. That timely break gives the 22-year-old a chance to serve for a place in the semi-finals.
5.58pmAce number 30 brings up three match points here for Janowicz!
Janowicz 7-5 6-4 6-4 KubotGAME SET AND MATCH! Tears on Court One as Jerzy Janowicz holds to love and secures a place in the semi-finals. A warm embrace between the two countrymen, as the 22-year-old becomes the first Polish man to reach the final four of a Grand Slam. A truly historic moment and terrific scenes between the two players!
6.03pmOn this evidence Janowicz will take some stopping and has further to go in his career. The 22-year-old can't hold back the tears as his momentous achievement kicks in. Kubot is waiting to walk off court with his Davis Cup teammate, quite a gesture from the veteran here.
6.06pmSuperb stuff on Court One and Janowicz will now await the winner of a tense clash on centre between Fernando Verdasco and Andy Murray.
6.09pmThat just about does it for coverage from this all-Polish men's quarter final, have we seen a future star of the sport emerge today in Jerzy Janowicz? I'll leave you to think that one over, good evening!