The hosts took the lead shortly after the half-hour mark when Diego Costa lashed a volley home from close range, but Troy Deeney's penalty ensured that the two sides would go into the break all square.
Odion Ighalo then scored in a club-record fifth consecutive top-flight match to give Watford the lead, but Costa's second of the game levelled things up less than 10 minutes later.
Chelsea should have won it late on when they were awarded a penalty, but Oscar slipped while taking his spot kick and blazed the effort well over.
Find out how all of the action unfolded courtesy of Sports Mole's live minute-by-minute coverage below.
2.30pmGood afternoon! Thank you very much for joining Sports Mole for the Boxing Day meeting between Chelsea and Watford in what is Guus Hiddink's first match back in charge of the team. It will not be an easy return, however, with Watford in magnificent form and eyeing yet another big scalp following their win over Liverpool last time out. First things first, though - let's have a look at the teams...
2.32pmCHELSEA STARTING XI: Courtois; Ivanovic, Cahill, Terry, Azpilicueta; Fabregas, Matic; Willian, Oscar, Pedro, Diego Costa
2.36pmWhat can we make of those two teams, then? Well, Hiddink has resisted the temptation to make any major changes for his first game back in charge, bringing in just one new face from the team that beat Sunderland last weekend as Gary Cahill replaces Kurt Zouma in the team. That means that the likes of Ivanovic, Fabregas and Costa, all of whom were booed by Chelsea fans last time out, once again start, while Eden Hazard returns to the bench following a hip injury.
2.38pmAs for Watford, they also make only one change, and that is an enforced one as Nathan Ake is ineligible to play against his parent club this afternoon. Jose Holebas comes in for his at left-back, but it is no surprise to see Quique Flores make no further changes. His side played very well against Liverpool last time out, particularly star striker Odion Ighalo. He now has 12 for the season in 17 games and 28 in 2015 - more than any other player in England's top four tiers. Another goal today would make him the first Watford player in history to have scored in five consecutive top-flight matches.
2.40pmChelsea have the task of stopping Ighalo, then, but there will be a renewed optimism around the club following the appointment of Guus Hiddink. The atmosphere in the stands was poisonous last week against Sunderland as fans made it clear that they still fully supported Jose Mourinho, chanting his name throughout the victory over the Black Cats and booing a number of their own players. However, Hiddink is also well-liked by the Chelsea fans, so there will surely be a more positive feeling inside the stadium this weekend.
2.42pmThere is good reason for Hiddink being liked by the Chelsea fans too. This is his second interim period in charge of Chelsea, and the first was highly successful. Having taken over from Luis Felipe Scolari, Hiddink lost just one of his 22 matches in all competitions, winning 16 of those and helping the team to FA Cup glory in 2009. He even holds a unique place in Premier League history, boasting the best win ratio of any manager to have taken charge of four or more games in the division (84.6%).
2.44pmThe Chelsea he took over then were in a much stronger position than the current team, though. Even with their win over Sunderland last weekend, Chelsea remain down in 15th place, only three points clear of the relegation zone courtesy of a truly terrible season so far. Their win over the Black Cats was only their second victory in eight Premier League games, while they are still looking for back-to-back Premier League wins for the first time this term - a feat they could achieve today.
2.46pmPerhaps the main positive for Chelsea to take from the season so far is that the other big teams are also struggling. Manchester United and Liverpool are dropping regular points, and the gap to the top four is still only 11 points for the Blues - still a big ask but certainly not unassailable. The gap to leaders Leicester is 20, and any hope of a meaningful title defence died a few weeks ago, but the top four does remain a target. It would take a substantial turnaround, but they certainly have the players to do it.
2.48pmNot that that will strike any fear into Watford, of course. The Hornets are absolutely flying at the moment having won four games on the bounce - already a club record for the Premier League and the first time they have managed it in the top flight since 1987. Another victory here would give them five in a row for the first time in the top flight, and it could remarkably also take them into the top four depending on results elsewhere. One of those results has already gone Watford's way with Manchester United losing in the early kickoff and, with only one point separating them from the Champions League places, it certainly isn't beyond the realms of possibility that they will end the day in the top four.
2.50pmNo-one would have tipped them to be so well placed approaching the halfway stage of the season having only been promoted in May, but they showed in a 3-0 victory over Liverpool last weekend that they can cause any team problems. There had been questions before the match due to their fairly poor record against top-half teams, but they put them to bed against the Reds. Of course, Chelsea are currently a bottom-half team, and Watford have a very good record against sides in the lower reaches this season, taking 21 points from a possible 27 and losing none of their nine games.
2.52pmThey have actually been better on the road than they have at home this season, picking up 14 points at both Vicarage Road and on their travels, but reaching that tally in fewer games away from home. They have won four and lost just one of their last six Premier League away games, while the only away games they have lost this season have been at Leicester and Manchester City - two teams in the top three. They have already won consecutive Premier League away games for the first time eber and for the first time in the top flight since 1987, and another win today would make it three on the bounce in the top flight for the first time ever.
2.54pmThey have already equalled their points tally for the 2006-07 season, their last in the Premier League, with more than half of this season to go. That has largely been built on a strong defence - only three teams have conceded fewer than Watford's 16 goals in 17 games this season. They have also kept clean sheets in their last three outings and stopped the opposition from scoring on eight occasions all season - second in the clean sheet rankings to only Manchester United.
2.55pmPREDICTION: We're nearing kickoff at Stamford Bridge, which means that it is time for a prediction! The form book suggests that Watford will win this one, but Chelsea under Hiddink should be a different proposition. New managers often give a team a boost, and I expect that to be the case today. I'm going for a 2-0 home victory.
2.57pmChelsea have dominated the recent history between these two sides, winning seven and losing none of their last eight meeting in all competitions. The aggregate scoreline in their last four meetings at Stamford Bridge is a whopping 16-0 to Chelsea, although Watford would have rarely made the short trip to West London in as good a position as they find themselves in now.
2.59pmIt is the second time that Chelsea have met Watford this year, having come up against the Hornets in the third round of the FA Cup back in January, when Willian, Remy and Zouma were on the scoresheet in a 3-0 victory at Stamford Bridge. They haven't met in the Premier League since March 2007, when Salomon Kalou scored a 92nd-minute winner in a 1-0 victory.
1 minKICKOFF: Watford get us underway at Stamford Bridge as they go in search of a fifth consecutive victory to spoil Hiddink's second coming at Chelsea.
3 minAs expected, there is a more positive feel around Stamford Bridge than there was in their last match. Mourinho's name as not been heard (yet) and the home fans seem to be getting behind the team.
4 minCHANCE! Big chance for Chelsea early on here as Oscar lifts a cross into the box for Costa, who gets in front of Cathcart well. He can't quite get above the ball, however, and plants his header over the top from close range.
6 minChelsea have knocked the ball around nicely in the opening exchanges of the game, looking confident in possession and comfortable playing the match at their own tempo.
8 minMore good football from the hosts as they knock it about before playing it out right for the overlapping Ivanovic. The ball eventually comes to Willian, whose deflected effort loops up and well over the crossbar.
9 minThe first corner comes to nothing, but Willian's second delivery is a dangerous one that bounces inside the six-yard box. Neither Costa or Ivanovic could get a touch as it went all the way through, though.
10 minCLOSE! Chelsea win a free kick in a dangerous crossing position, and Willian is as dangerous as anyone over a dead ball at the moment. This delivery takes a big deflection of Abdi, but that almost helps the hosts as the ball loops over Gomes and drops just past the far post.
12 minChelsea have enjoyed more than 80% possession in this match so far, which goes to show just how this game has started. Watford have made a very slow start to the game, although Gomes is still yet to be tested in the visitors' goal.
14 minAs has been the case for much of this season, Willian has looked like Chelsea's most dangerous player so far. He is linking up well with those around him in open play, while his dead-ball deliveries are asking questions too.
16 minWatford are just starting to come into the match a little more now, although Ighalo and Deeney have so far been kept very quiet and Courtois has had nothing to do.
18 minCHANCE! Well, Courtois has still had nothing to do, but Watford probably should be ahead here. Their first chance of the match falls to the man they would want as he beats the offside to latch on to a bobbling, mis-hit effort from outside the area. He probably has more time than he feels, though, snatching at his effort and skewing it wide when he probably should have scored.
19 minCosta almost gets in at the other end as the ball breaks to him inside the area, but Gomes is quickly off his line to smother it at the Spaniard's feet.
20 minMore good play from Ighalo in the Chelsea box as he pulls out what is quickly becoming his renowned party piece. He squares up Terry and Cahill before dragging the ball past the both of them, but he shows just too much of it to Courtois.
22 minChelsea really started this match brightly, but it is pretty even now and Watford are very much in the game. Neither keeper has yet been seriously tested, though.
23 minCHANCE! Another sight of goal for Ighalo, this time from a corner as he towers above Azpilicueta only to plant a header wide of the post. Again, he will be disappointed that he didn't do better there.
25 minUPDATE: Being Boxing Day, we have a full set of Premier League fixtures going on at the moment, and there have been a few goals already. Manchester City have blitzed Sunderland in the opening 25 minutes and lead 3-0, while Spurs and Swansea are one up against West Brom and Norwich respectively.
27 minIt is Watford who are looking the most likely at the moment, and Ighalo has another shooting opportunity here as Jurado advances down the left before playing the ball back to the edge of the area. Ighalo volleys it, but it isn't a good strike and hits Deeney on the way through.
29 minYet another shooting chance for Watford! This time it falls to Abdi as the space opens up for the midfielder, only for him to send a volley over the crossbar.
31 minWatford are getting plenty of joy down their left flank at the moment, with Holebas and Jurado causing Ivanovic all sorts of problems on that side of the field. The visitors are the better side right now.
32 minI believe that is known as the commentator's curse. Following a good spell from Watford, it is Chelsea who take the lead just after the half-hour mark. Willian's corner is met by Terry, whose header hits the back of Cahill and falls into the path of Costa right on the edge of the six-yard box. The striker hits it first time on the turn, connecting sweetly with the volley to leave Gomes no chance whatsoever.
34 minThat goal came at a very good time for Chelsea. The fans were beginning to get a little frustrated by their side's performance, with Watford looking the more dangerous of the two teams. The opener has changed the atmosphere inside Stamford Bridge again, though.
38 minWillian again provides the danger down the right as Britos is forced to concede another corner, but Watford are just about able to deal with this one despite another testing delivery from the Brazilian.
39 minCHANCE! Good chance for Chelsea to double their advantage as Ivanovic picks the ball up on the right flank before beating Watson on his way to the byline. His pull-back finds Oscar, but he leans back when going for goal and puts his shot over the crossbar.
40 minDecent chance for Watford to get the equaliser here as Ighalo wins a free kick in a very dangerous position...
41 minCLOSE! It is a good effort from Jurado as he curls it over the wall and just past the post, although the shot did take a deflection on the way through and it will be a corner for Watford.
42 minGOAL! Chelsea 1-1 Watford (Troy Deeney, pen)
42 minWatford level things up before the interval, but what on earth is Matic doing to give away a penalty?! It really is dreadful from the midfielder, who had his hands needlessly in the air when Watson's corner came into the box. It strikes one of those hands, and Andre Marriner correctly points to the spot. Up steps Deeney, and he makes no mistake to send Courtois the wrong way.
44 minYELLOW CARD! Britos gets his name taken by Marriner for a foul on Costa just outside the Watford box. Can Chelsea come up with an instant reply here?
45 minSHOT! Unsurprisingly it is Willian who takes the free kick on, but his effort flies comfortably over the crossbar.
45 minThere will be one minute of added time at the end of this first half.
45+1 minBrilliant from Pedro as he feeds a beauty of a low cross right into the six-yard box. It is perfectly weighted between defence and goalkeeper, but is also just too far in front of Costa.
3.56pmAndre Marriner brings the first half to an end at Stamford Bridge, then, and it is all square between Chelsea and Watford. The Blues have not exactly shown a vast improvement under Hiddink in his first game back in charge, and Watford certainly deserve to be level at the break having created the better chances in that opening 45 minutes.
3.58pmDiego Costa got the opening goal of the contest shortly after the half-hour mark when the ball dropped to him inside the box after Terry's header had deflected off Cahill. There was an element of luck of how it fell to Costa, but the finish was a clean one as the striker lashed a volley past a helpless Gomes on the turn.
4pmWatford got the equaliser in the closing stages of the half, however, and it came from the penalty spot as Deeney sent Courtois the wrong way from 12 yards. It really was a gift for the visitors from Matic, who bizarrely handled the ball from a Ben Watson corner under no pressure whatsoever. Quite what the midfielder was thinking, only he will know, but Watford didn't wait around to ask any questions.
4.02pmBoth sides have had chances aside from their goals too, with Watford's best falling to Ighalo. However, the in-form striker snatched at his first effort and misplaced a header with his second, putting both wide of the target. For Chelsea, meanwhile, Costa missed an early header, while Oscar has blazed a very presentable chance over the top when the score was 1-0.
46 minKICKOFF: We're back underway at Stamford Bridge as Chelsea kick us off again. The first thing to tell you is that the hosts have made a change at the break, and it is an interesting one as Fabregas is replaced by John Obi Mikel - not exactly an attacking switch.
46 minAn early break forward for Chelsea in the second half as Willian slides a pass in to Azpilicueta, who in turn feeds a low cross into a good area. Pedro is a couple of yards behind the play, though, and Holebas is able to clear.
48 minYELLOW CARD! Cathcart joins his fellow centre-back Britos in the book for a trip on Costa as Chelsea were looking to launch a counter-attack.
49 minTwo penalty shouts for Chelsea in quick succession as first Ivanovic goes down under the challenge of Britos, while the same Watford defender is subject to a handball claim from the resulting corner. There is no doubt about the first one - it was a good, clean tackle - and the second would have been a little harsh too.
51 minWatford are giving Chelsea very little time on the ball whatsoever. They are right in the faces of the hosts, which is making things very difficult for Chelsea.
53 minIt is all rather scrappy at the moment as both sides struggle to keep hold of the ball for any real length of time. Chelsea are enjoying the lion's share of possession, but Watford are doing a good job of breaking things up.
56 minIt is history for Ighalo! Moments after Capoue has a couple of efforts on goal blocked, Watford do complete the turnaround to take the lead at Stamford Bridge. Ighalo works space to shoot and his effort takes a slight deflection on its way through to beat Courtois. That is five consecutive games in which Ighalo has scored, which is a new top-flight record for the Hornets.
60 minAnother penalty shout for Chelsea, but again Andre Marriner is right to wave the claims away. A cross comes into the box and Oscar looks like he wants to go for an acrobatic volley on the turn, only to go down under the challenge of Britos. There is not enough in it, though, and play continues once again.
62 minCHANCE! Really good defensive work by Watson to deny Chelsea a big chance! Oscar brings the ball into the area down the right, cutting inside before teeing up Pedro for what looks to be a glorious opening, However, Watson is quickly there to block the shot before it can test Gomes.
65 minChelsea are back level, and it is Diego Costa who doubles his personal tally for the afternoon. Willian is once again the creator, sliding a defence-splitting pass in to Costa, who has made a good run in behind the back four. It is a good finish from the striker too as he takes one touch before planting his finish past Gomes.
67 minCan Watford respond again now? They would probably be happy with a draw at Stamford Bridge, but it was been a fairly even and open game so far so they are very much in with a shout of getting all three points here.
68 minCHANCE! Good chance for Costa to get his hat-trick here! Oscar sends a lovely low cross in towards the near post with the outside of his boot that Costa attacks. He gets to the ball first too, but his shot goes wide via the leg of Gomes.
69 minWATFORD SUB: The visitors make a change here as Valon Behrami replaces Abdi for the final 20 minutes or so.
72 minDecent chance for Willian again as he picks the ball up in a bit of space over to the right side of the box. However, he is always looking for a teammate, and eventually makes the wrong decision with the pass, sending it straight to Gomes.
73 minWATFORD SUB: Another change for the hosts here as Ikechi Anya comes on to replace Jurado.
75 minCHELSEA SUB: It is time for Eden Hazard, who gets a decent reception from the Chelsea fans on his return to the side after a short period out through injury. Pedro is the man to make way.
76 minChance for Chelsea here as Watson brings Willian down in almost a perfect shooting opportunity for a free kick. Willian, as ever, is the man standing over it.
77 minSHOT! It is better than his first-half effort, but still not really causing Gomes any problems as it flies a couple of yards over the top.
80 minOh my word, Chelsea miss a glorious chance to regain the lead here! It is a truly dreadful penalty from Oscar as he slips while taking it, sending his spot kick a long, long way over the bar. Once again it was the correct decision from Andre Marriner to point to the spot as Behrami clattered into Hazard with a rash challenge, but the visitors get away with it!
82 minYELLOW CARD! Behrami goes into the book for a challenge on Azpilicueta, where he came over the top a little. He didn't make much contact with the full-back in truth, but it still could have been a dangerous challenge. Holebas was also put into the book shortly after Oscar's missed penalty, incidentally.
84 minBehrami is a little fortunate in truth as he probably deserved a card for the tackle that gave away the penalty. Some would argue that his challenge on Azpilicueta there was worthy of a red card in itself, so the sub could well have been sent off already here.
87 minWillian has been a real livewire throughout this match. Again he makes headway down the right, nicking the ball off Holebas and advancing forward. However, he makes the wrong decision and gives the ball away when looking for a teammate on the edge of the box.
87 minCHANCES! Good work again from Ighalo as he cuts in from the left before seeing his shot blocked. The rebound falls to Deeney, but the captain's effort is also blocked as Chelsea survive a late scare.
88 minYELLOW CARD! Costa goes into the book for Chelsea following a poor challenge on the halfway line, although he did appear to slip into it a little.
90 minThere will be four minutes of added time at the end of this match.
90+3 minWATFORD SUB: A third and final change for the visitors sees Deeney depart to be replaced by Adlene Guedioura.
4.58pmIt ends all square in Guus Hiddink's first match back in charge of Chelsea, then! Diego Costa got both goals for the hosts, but Watford's dynamic duo of Troy Deeney and Odion Ighalo once again earned the Hornets an impressive point as they make it five unbeaten.
5pmThat is all we have time for this afternoon! Thank you very much for joining Sports Mole for an entertaining contest as Chelsea and Watford share four goals at Stamford Bridge. I will leave you with our match report, and be sure to stick around for reaction from both camps. From me, though, it is goodbye for now!