Match ends, Watford 1, Crystal Palace 1.
Watford 1-1 Crystal Palace
Troy Deeney scored a second-half penalty to equalise for Watford as Sam Allardyce took a point on his return to management with Crystal Palace.
After dominating in the opening stages, Palace went ahead through Yohan Cabaye's low strike in the 26th minute.
The visitors missed the chance to double their lead when Christian Benteke's penalty was saved by Heurelho Gomes after the Watford goalkeeper had fouled the Belgian.
Deeney converted his penalty - after Sebastian Prodl was fouled - to end a 10-game goalless run and score his 100th Watford goal.
The point for Palace, who sacked Alan Pardew as manager on Thursday before appointing former England boss Allardyce the following day, comes after back-to-back defeats and moves them two points clear of the relegation zone.
Watford climbed to 10th before seven more Premier League matches on Boxing Day.
Familiar Palace problems halt Big Sam
Allardyce said he hoped to "bring some joy, particularly over Christmas and New Year" when he started his first management role since his ill-fated 67 days as England boss, but another soft goal prevented a perfect start at the club.
Palace have failed to keep a clean sheet in 22 of their last 23 Premier League games and have conceded 33 goals this season with only Swansea and Hull - in 19th and 20th respectively - conceding more.
Allardyce's teams are renowned for the defending of set pieces and the 62-year-old will no doubt be disappointed with Watford's equaliser.
Referee Mark Clattenburg gave a foul against Palace defender Damien Delaney for pulling back Prodl at a corner before Deeney fired home from the spot.
A tale of two penalties
Palace chairman Steve Parish said the club's "expansive style of football hasn't worked" and they need to "wind the dial back the other way" following Allardyce's appointment.
The new manager named an attacking starting line-up, however, recalling winger Andros Townsend who had been left out of the starting XI for the Eagles' previous two games.
It was the England winger who set up Cabaye for Palace's goal with his first assist for the club since joining from Newcastle in the summer.
The Eagles dominated the first half - helped by the fact defender Daryl Janmaat and midfielder Valon Behrami both went off injured for Watford within the opening 15 minutes - and would have fully deserved a two-goal lead had Benteke converted from the spot.
The Belgian used his usual stuttered run-up for the spot-kick, which lacked power and was comfortably saved by Gomes.
Watford improved after the break - producing eight of their nine shots in the second half - and punished the Belgian for his miss.
By contrast, Deeney blasted his penalty down the middle to beat Wayne Hennessey.
"When you're not having the best of moments in front of goal, just smash it down the middle," said the 28-year-old, who had not scored since the beginning of October.
Palace had a late appeal for another penalty turned down by Clattenburg when Miguel Britos tackled Wilfried Zaha but the referee chose to book the winger for simulation.
When asked if he thought the decision to award Palace a penalty was soft, Allardyce said: "Not really, you grab players in the box knowing some referees give it and some don't.
"The Watford player himself did a great job of rolling over and Clattenburg saw it but I am still bemused he didn't give the one for Zaha," he added.
"There was contact there and he gets booked for it, while Gomes does a hatchet job and doesn't even get booked."
What they said
Watford manager Walter Mazzarri, speaking to BBC Sport: "I'm happy with the point. But today is the first game I don't like since I am here.
"Everything is happening to us because we had two injured players after 15 minutes and that can change any team, but still today the players could have done much better. It was not only one or two but many of them. So I am not happy with this.
"I am happy with the point and that Deeney scored his 100th goal - that had been a heavy weight he was carrying. Now this is over."
Crystal Palace manager Sam Allardyce, speaking to BBC Sport: "The missed penalty, that was a big moment in the game, then we gave a soft penalty away when we had hardly looked in danger at all. We just didn't finish the opposition off.
"You are a bit apprehensive about what you have got, but from I have seen we have some real talent. I just have to build the resilience a bit more and we will be OK."
Man of the match - Wilfried Zaha (Crystal Palace)
Big Sam's opening day blues - the best stats
- Sam Allardyce has failed to win his first Premier League game in charge with both of his last two clubs (also Sunderland), after winning each of the previous four (Bolton, Newcastle, Blackburn and West Ham).
- Troy Deeney became the fifth player to score 100 goals in all competitions for Watford after Luther Blissett, Tommy Barnett, Ross Jenkins and Cliff Holton.
- Deeney is now Watford's all-time leading scorer in Premier League history (17 goals); one ahead of Odion Ighalo (16).
- Christian Benteke has missed more penalties this season than any other Premier League player (two).
- Today was the fourth time in Premier League history that a club has had two starting players subbed off in the opening 15 minutes.
- Yohan Cabaye has scored in both of his Premier League appearances at Vicarage Road.
Allardyce's second game in charge of Crystal Palace is a trip to Emirates Stadium to play Arsenal on New Year's Day (kick-off 16:00 GMT). Watford host Tottenham on the same day (kick-off 13:30 GMT).
- 3BritosBooked at 90mins
- 22JanmaatSubstituted forZuñigaat 4'minutesSubstituted forSinclairat 85'minutes
- 11BehramiSubstituted forDeeneyat 14'minutes
- 25HolebasBooked at 53mins
- 27DelaneyBooked at 70mins
- 4FlaminiSubstituted forCampbellat 81'minutes
- 10TownsendSubstituted forMutchat 74'minutes
- 42PuncheonBooked at 45mins
- 11ZahaBooked at 87mins
- 17BentekeBooked at 45mins
- 14Lee Chung-yong
- Mark Clattenburg
- Shots on Target
Second Half ends, Watford 1, Crystal Palace 1.
Foul by Jerome Sinclair (Watford).
Yohan Cabaye (Crystal Palace) wins a free kick in the defensive half.
Miguel Britos (Watford) is shown the yellow card for a bad foul.
Foul by Miguel Britos (Watford).
Christian Benteke (Crystal Palace) wins a free kick in the attacking half.
Attempt saved. Adlène Guédioura (Watford) left footed shot from outside the box is saved in the bottom left corner.
Etienne Capoue (Watford) wins a free kick in the attacking half.
Foul by Jason Puncheon (Crystal Palace).
Wilfried Zaha (Crystal Palace) is shown the yellow card.
Wilfried Zaha (Crystal Palace) has gone down, but that's a dive.
Miguel Britos (Watford) wins a free kick in the defensive half.
Foul by Wilfried Zaha (Crystal Palace).
Substitution, Watford. Jerome Sinclair replaces Juan Zuñiga.
Delay over. They are ready to continue.
Delay in match Troy Deeney (Watford) because of an injury.
Attempt saved. Odion Ighalo (Watford) header from the centre of the box is saved in the centre of the goal. Assisted by Adlène Guédioura with a cross.
Offside, Crystal Palace. Damien Delaney tries a through ball, but Christian Benteke is caught offside.
Substitution, Crystal Palace. Fraizer Campbell replaces Mathieu Flamini.
Foul by José Holebas (Watford).
Wilfried Zaha (Crystal Palace) wins a free kick on the right wing.
Foul by Adlène Guédioura (Watford).
Jordon Mutch (Crystal Palace) wins a free kick in the attacking half.
Foul by Adlène Guédioura (Watford).
Wilfried Zaha (Crystal Palace) wins a free kick in the defensive half.
Corner, Watford. Conceded by Damien Delaney.
Foul by Miguel Britos (Watford).
Martin Kelly (Crystal Palace) wins a free kick in the defensive half.
Corner, Watford. Conceded by Yohan Cabaye.
Substitution, Crystal Palace. Jordon Mutch replaces Andros Townsend.
Attempt missed. Scott Dann (Crystal Palace) header from the centre of the box is too high. Assisted by Jason Puncheon with a cross following a set piece situation.
Foul by Sebastian Prödl (Watford).
Wilfried Zaha (Crystal Palace) wins a free kick in the attacking half.
Goal! Watford 1, Crystal Palace 1. Troy Deeney (Watford) converts the penalty with a right footed shot to the centre of the goal.
Damien Delaney (Crystal Palace) is shown the yellow card for a bad foul.
Penalty Watford. Sebastian Prödl draws a foul in the penalty area.
Penalty conceded by Damien Delaney (Crystal Palace) after a foul in the penalty area.
Corner, Watford. Conceded by Andros Townsend.
Attempt missed. Juan Zuñiga (Watford) right footed shot from outside the box is too high. Assisted by Troy Deeney with a headed pass following a set piece situation.