Match ends, Preston North End 1, Watford 0.
Championship Preston reached round three of the Capital One Cup as Marnick Vermijl's goal saw off Premier League Watford, who finished with 10 men.
Defender Vermijl, on loan from Sheffield Wednesday, scored from inside the box after Josh Brownhill's eighth-minute shot had been blocked.
It was enough to condemn the Hornets to a first defeat this season.
Watford debutant Miguel Britos received a straight red card with 15 minutes left for an elbow on Bailey Wright.
With Saturday's trip to leaders Manchester City in mind, the Hornets made 11 changes to the side that started Sunday's 0-0 draw with Southampton.
But Quique Sanchez Flores' understudies failed to impress as Preston sealed a deserved win.
Watford finally began to exert some pressure as the second half wore on, but Britos's dismissal after the Uruguayan had gone up for a corner halted the Hornets' momentum, and Preston were able to see out the final 15 minutes with relative ease.
They came close to adding to their lead when former Watford striker Joe Garner saw a long-range effort deflected narrowly wide.
- 15WoodsBooked at 34mins
- 14GarnerSubstituted forBeckfordat 84'minutes
- 17ReidBooked at 64minsSubstituted forHumphreyat 84'minutes
- 3BritosBooked at 75mins
- 28SmithSubstituted forBerghuisat 59'minutes
- 10VydraBooked at 39mins
- Steve Martin
- Shots on Target
Second Half ends, Preston North End 1, Watford 0.
Attempt missed. Ben Watson (Watford) header from the centre of the box misses to the left.
Foul by Paul Huntington (Preston North End).
Matej Vydra (Watford) wins a free kick in the defensive half.
Attempt missed. Chris Humphrey (Preston North End) right footed shot from long range on the right is close, but misses to the left.
Foul by Jermaine Beckford (Preston North End).
Fernando Forestieri (Watford) wins a free kick on the right wing.
Substitution, Preston North End. Jermaine Beckford replaces Joe Garner.
Substitution, Preston North End. Chris Humphrey replaces Kyel Reid.
Joe Garner (Preston North End) wins a free kick in the defensive half.
Foul by Gabriele Angella (Watford).
Neil Kilkenny (Preston North End) wins a free kick on the right wing.
Foul by Steven Berghuis (Watford).
Corner, Preston North End. Conceded by Gabriele Angella.
Attempt blocked. Joe Garner (Preston North End) right footed shot from outside the box is blocked.
Attempt missed. Kyel Reid (Preston North End) right footed shot from the left side of the box misses to the right.
Miguel Britos (Watford) is shown the red card for violent conduct.
Corner, Watford. Conceded by Jordan Pickford.
Attempt saved. Ben Watson (Watford) right footed shot from a difficult angle and long range on the right is saved in the top left corner.