Defender Danny Maddix gave rock bottom Sheffield Wednesday the slenderest of lifelines with a last-gasp equaliser and his first goal of the season.
But Wednesday still look like condemned men as they try desperately to cling on to first division football.
Watford substitute Jason Norville looked to have killed off Wednesday but Maddix headed in a Richard Evans corner with the last touch of the game.
On-loan striker Lee Bradbury had given Wednesday hope with a penalty equaliser after Tommy Smith's opener, but Norville mad it 2-1 nine minutes from the end.
Michael Reddy, on loan from Sunderland, showed a flash of quality early on for Wednesday but his sharp shot brought a super save from veteran keeper Alec Chamberlain.
And when Reddy pulled a clever ball across the goal from the right Wednesday had no one in the middle.
And Chamberlain did well when Tony Crane produced a header after a cross from new boy Evans, brought in from Birmingham.
Despite hogging the early pressure Wednesday failed to produce an opener and more danger came on the break when Smith headed over from a Stephen Glass cross.
It was the 22-year-old frontman Smith who struck first to give Watford the lead after 33 minutes with his ninth of the season.
A corner from Neal Ardley was headed clear, but Paolo Vernazza pounced and drilled a shot into the crowded area. The ball squeezed through and Smith showed lightning reactions to seize on to the ball and smash in a close-range shot.
But substitute Lloyd Owusu won a penalty after 64 minutes when he headed over Chamberlain but was bulldozed by the keeper. Bradbury tucked away the spot-kick for his second goal for the club.
Norville scored following a breakaway after 81 minutes lashing in a shot from 15 yards, before in injury time Evans swung in a corner for Maddix to head in the equaliser.