Tom Cleverleys winner helped 10-man Watford extend their good start to the Championship season and end Burnleys unbeaten start under Vincent Kompany.
The hosts led with the games first effort on target just before half-time as Joao Pedros neat touch freed Ismaila Sarr, whose pull-back found Cleverley to side-foot into the bottom corner.
Josh Brownhill was twice denied by smart saves from Hornets goalkeeper Daniel Bachmann as the Clarets improved after the break.
The hosts lost full-back Hassane Kamara to a straight red card for pulling back Vitinho as he bore down on goal, and Brownhill then turned the Brazilians cross against the bar, but Watford held out.
More to follow.
Match ends, Watford 1, Burnley 0.
Second Half ends, Watford 1, Burnley 0.
Attempt saved. Luke McNally (Burnley) right footed shot from the centre of the box is saved in the centre of the goal. Assisted by Ian Maatsen.
Hand ball by Jay Rodríguez (Burnley).
Josh Brownhill (Burnley) hits the bar with a right footed shot from the centre of the box. Assisted by Vitinho with a cross.
Substitution, Burnley. Luke McNally replaces Josh Cullen.
Offside, Burnley. Connor Roberts tries a through ball, but Jay Rodríguez is caught offside.
Yáser Asprilla (Watford) is shown the yellow card.
Ian Maatsen (Burnley) wins a free kick on the left wing.
Foul by Yáser Asprilla (Watford).
Foul by Josh Cullen (Burnley).
Edo Kayembe (Watford) wins a free kick on the right wing.
Josh Brownhill (Burnley) is shown the yellow card for a bad foul.
Foul by Josh Brownhill (Burnley).
Dan Gosling (Watford) wins a free kick in the defensive half.
Corner, Burnley. Conceded by Daniel Bachmann.
Attempt saved. Josh Brownhill (Burnley) right footed shot from outside the box is saved in the top right corner.
Substitution, Watford. Christian Kabasele replaces Hamza Choudhury.
Hassane Kamara (Watford) is shown the red card.
Vitinho (Burnley) wins a free kick in the attacking half.