Leeds picked up their first victory in the Premier League this season as defender Diego Llorente returned from injury to score the winner over Watford.
Llorente, who picked up a hamstring injury in the defeat by Liverpool, instinctively poked it in from close range after a corner delivery bounced off Watford's Juraj Kucka at the back post.
It capped off a dominant first-half display from Leeds but failure to take their chances made for a nervy ending.
Watford, who were sloppy in possession and passive for large parts of the game, had a goal ruled out in the second half for a foul in the build-up after goalkeeper Illan Meslier's fumble almost proved costly.