Watford's John Eustace grabbed a dramatic injury-time equaliser to deny 10-man Bristol City victory.
Danny Haynes put the visitors in front in the 38th minute before on-loan midfielder Tom Cleverley equalised with a fierce drive five minutes later.
But Paul Hartley regained the lead for City with a fine 30-yard free-kick on the stroke of half time.
Lewin Nyatanga was red carded in the 79th minute before Eustace bundled in from close range to earn a point.
The goal came in the 93rd minute and was deserved reward for a spirited display by the home side, who had two Heidar Helguson goals disallowed by the officials.
Neither side have recorded a victory in four games and are level on 32 points in the league.
Haynes notched his fourth of the season after excellent work from David Clarkson, but Manchester United midfielder Cleverley, who has impressed during his loan spell at Vicarage Road, punished a poor Jamie McAllister clearance to smash the equaliser two minutes from time.
But the Hornets conceded two minutes into first-half stoppage time courtesy of Hartley's powerful free-kick.
City keeper Dean Gerken produced a superb one-handed save to deny Danny Graham in the second half before denying Helguson minutes later.
Nyatanga's dismissal for a second yellow card issued for a foul on on-loan midfielder Henri Lansbury allowed Watford to push forward.
And they were rewarded right at the death as Eustace latched on to Helguson's touch.
Bristol City manager Gary Johnson on his side conceding a stoppage-time goal for the fourth time in seven game: "Again we have let in a last-gasp equaliser and feel like we have lost, rather than drawn.
"I don't know what more we can do except to keep drilling the players on how to clear their lines.
"At the moment when the stoppage time board goes up it seems to create a siege mentality and we cannot hold onto the ball. It has cost us so many points this season and I'm more than frustrated by it."
Watford manager Malky Mackay:
"We have a young side and I'm very proud of the way they kept battling right up until the final whistle.
"City's goalkeeper has pulled off a string of fine saves in the second half and I was starting to think it just wasn't going to be our day.
"But we knew of their tendency to let in late goals so when five minutes of stoppage time was signalled I felt we still had every chance."
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