Substitute Andre Ayew scored a second-half equaliser to earn West Ham a Premier League point against Watford.
The hosts went ahead on three minutes through Troy Deeney's penalty after Mauro Zarate was brought down in the box by Cheikhou Kouyate.
Just three minutes later they could have doubled their advantage but M'Baye Niang's powerful drive flew narrowly over the crossbar.
The game was held up for a lengthy period just before half-time when West Ham's Zarate went down with a knee injury. He was taken to hospital for a scan to determine the extent of the problem.
Watford goalkeeper Heurelho Gomes brilliantly kept out Jose Fonte's header with a full-stretch save, before Michail Antonio's low shot struck both posts and Ayew was on hand to tuck in the rebound.
Hammers midfielder Antonio was dismissed with five minutes to go after receiving a second yellow card for deliberate handball.
The result moved both sides up a place in the table. The Hornets climbed to 12th, while the Hammers go ninth.
Relive the draw between Watford and West Ham
Mixed match for West Ham
Slaven Bilic's side had fallen behind early in the game, but showed their fight by continuing to push forward and getting their reward in the second half to gain a point.
Striker Ayew came off the bench to claim just his second goal in a Hammers shirt as the ball kindly fell to him inside the box following Antonio's effort.
It was Ayew's 14th Premier League goal and the the Ghanaian has now netted against 13 different teams in the division.
Having hit the woodwork, former Nottingham Forest man Antonio should have got on the scoresheet but headed narrowly wide from close range after Aaron Cresswell's cross.
His unfortunate match got worse late on when he was given the first red card of his professional career and West Ham also had Argentine Zarate - who won the penalty - taken off on a stretcher after appearing to twist his knee in the first half.
Deeney's spot-kick was his fourth goal in his past five games and Watford's only shot on target in the entire match.
Since the start of last season, Deeney has scored nine penalties, the joint highest tally with Tottenham's Harry Kane.
If they failed to trouble West Ham goalkeeper Darren Randolph after the penalty, it looked like the Hornets might at least hold out at the other end, but Walter Mazzarri's side now have just just one clean sheet in their past 16 games.
They could even have snatched a win in injury time, but substitute Isaac Success was not able to get any contact on Deeney's knock-down in the box.
Watford host Southampton in the league next Saturday (kick-off 15:00 GMT), while West Ham face Chelsea on Monday, 6 March (kick-off 20:00 GMT).
More to follow.