Nyron Nosworthy's late leveller dealt a blow to Cardiff City's stuttering play-off charge as the defender rescued mid-table Watford a Championship point.
Scotland striker Kenny Miller had headed Cardiff into a first-half lead as he converted Don Cowie's cross to end his 15-match goalless streak.
Miller then hit the post before Watford started to capitalise on the Bluebirds' nerves as Troy Deeney went close.
Then an unmarked Nosworthy guided Sean Murray's free-kick in to level.
The centre-back's second goal in nine years extended Cardiff's miserable winless home run to six games so Brighton have the chance to replace the Welsh club in the play-off places on Tuesday should they beat in-form Reading at home.
Cardiff remain sixth in the table and while they are unbeaten in seven games, they dropped points for the sixth time in seven league games when Malky Mackay hoped to be strengthening their promotion credentials.
Watford, meanwhile, showed their resilience to force an eighth away draw of the season and maintain their outside chance of their own top six finish.
The Hornets have suffered just one defeat in their last nine matches, although making up a seven point difference with four games remaining will be difficult.
Cardiff, though, were left to rue missed chances as Ben Turner's early header from Peter Whittingham flashed wide.
And Craig Conway, returning to Cardiff's starting line-up for the first time in two months, cracked a long-range half-volley narrowly wide of the far post.
The Bluebirds had shaded a poor first half and broke the deadlock in injury-time as Miller guided in his first goal since 21 January.
A knee injury forced the 32-year-old off early in Saturday's win at Middlesbrough and only played at the Cardiff City Stadium after passing a late fitness test, but Miller was glad he did as he ended one of his worst scoring droughts in his career.
Cowie sped onto Kevin McNaughton's ball down the right flank and the all-Scottish move was completed by Miller when he lost his marker to head in his 11th goal of the season.
And Miller was only inches away from adding a second just after the break as the striker fired Liam Lawrence's low cross against the Watford post.
But Watford rallied and started to dominate the hosts, giving Cardiff a scare when Martin Taylor's firm header from Murray's corner brought the best out of Bluebirds keeper David Marshall.
Troy Deeney then had an effort cleared off the line by Miller while Watford also had a penalty appeal rejected after Taylor went down under pressure from Mark Hudson.
Deeney squandered another glorious chance when he fired over from point blank range after getting in front of Hudson to latch on to substitute Joe Garner's cross.
Miller, though, almost prized open the Watford defence again with an exquisite chip but Aron Gunnarsson could not direct his header past Hornets keeper Tomasz Kuszczak.
Nosworthy, who was signed in January from Premier League Sunderland, saved Sean Dyche's men as he poked in from Murray's right-wing free-kick to continue Watford's impressive five-match unbeaten away run.