WATFORD 1 (Kightly 27), UNITED 1 (Snodgrass 90+4 pen)
Watford: Loach, Hodson, Dickinson, Mariappa, Yeates, Deeney, Kightly Eustace 77), Buaben, Sordell, Hogg, Nosworthy. Subs: Bond, Iwelumo, Mirfin, Beattie.
United: McCarthy, Connolly, Lees, Kisnorbo, White, Sam (Vayrynen 62), Pugh, Clayton, Snodgrass, Becchio, Keogh (McCormack 63). Subs: Lonergan, Brown, O'Dea.
Referee: E Ilderton
Att: 13,573 (2,062 Leeds)
United manager Simon Grayson was forced into shuffling his pack for the trip to Watford with skipper Jonny Howson sidelined with a knee injury and Michael Brown still feeling the effects of a knock on the ankle.
The changes meant for a change of system with Danny Pugh operating in a central midfield role, alongside Adam Clayton while Andy Keogh partnered Luciano Becchio in the front line.
It was a quite an open start to the contest with both sides looking to drive forward when in possession. Watford got in a couple of early crosses while Robert Snodgrass had one shot blocked when he was given space on the edge of the box.
Pugh also lifted a shot over the top in the 11th minute after more good attacking play by Leeds. At the other end Marvin Sordell screwed a shot wide after he found space to create an opening.
United threatened again when Snodgrass was again given space, but his shot from distance was wide of the mark. Snodgrass also delivered two good corners, the second of which Tom Lees narrowly failed to connect with.
United won a series of corners, but when Watford broke after one Leeds attack, Michael Kightly was able to capitalise on some sloppy defending and after advancing, he lashed the ball beyond the reach of Alex McCarthy.
While Leeds had been good enough in possession, Watford looked equally good with the ball and were causing United problems with good movement.
United did have an opportunity to get back in the game on 40 minutes, but Snodgras bent a shot wide of the past when, despite goalkeeper Scott Loach being drawn, there were four Watford men on the line.
Luciano Becchio was also denied following a good cross from the right as the game headed towards half-time, whjile Andy Keogh looked to referee Eddie Ilderton after going down in the box while trying to force an opening.
Lloyd Sam also put an effort wide right on the stroke of half-time after more good work by Keogh.
The second half opened up as a stop-start affair. Becchio did lift an ambitious attempt over the top from distance while the hosts also sent a shot wide of the mark after again finding good space.
McCarthy also had to get down well to save a low effort from Troy Deeney while Sordell lifted a shot over the bar after capitalising on some sloppiness at the back.
Shortly after the hour, Grayson made a double change, introducing Mika Vayrynen and Ross McCormack. It also prompted a change in system with Aidy White and Snodgrass moving into advanced wide roles.
There was no immediate imact with the changes as Watford continued to look the more likely side. White was thwarted on one advancing run and with 15 minutes remaining Snodgrass was crowded out as he looked to progress on the edge of the box.
But as the game headed towards the final five minutes, United were looking increasingly unlikely in the bid to force an equaliser with Watford looking well organised and resolute.
A rare hashed clearance allowed Becchio a half-chance, but the striker's first time shot was wide of the mark.
And with two minutes remaining, Sordell went down under pressure from Kisnorbo and Watford were awarded a penalty. Sordell stepped up, but McCarthy got a vital fingertip and pushed his penalty onto the post.
Moments later, the United keeper made another excellent save and Leeds were facing three minutes of added time in the hope of salvaging a draw.
But there was drama in the 94th minute at the other end when Mika Vayrynen was brought down and Ilderton awarded Leeds a penalty.
Snodgrass was the man who stepped up and he made no mistake in smashing home an equaliser with the last kick of the game to send the 2,000 travelling fans into ecstasy.