Manchester United put in a poor all-round display at Vicarage Road to go down 1-3 to Watford in the Premier League and record their third successive defeat in a week.
Manager Jose Mourinho made five changes to the side which lost 1-0 at Feyenoord in their mid-week Europa League fixture. Wayne Rooney, Zlatan Ibrahimovic, Marouanne Fellaini, Luke Shaw and Antonio Valencia came in for Juan Mata, Ander Herrera, Morgan Schneiderlin, Marcos Rojo and Matteo Darmian.
The Hornets (as Watford are known) took the lead at home through Etienne Capoue's opener after Daryl Janmaat had sent in a low cross from the right. The goal was contentious as replays showed that Anthony Martial had been fouled in the build-up to the goal. United went in to half-time a goal down as Mourinho was forced into an early substitution with the injured Martial taken off for Ashley Young.
United pushed and prodded at the start of the second half as Ibrahimovic's cross from the left hand side found its way to Marcus Rashford, who made no mistake in sliding the ball under Heurelho Gomes and draw the visitors level.
Gomes pulled off a fine save as a Fellaini ball from deep found the head of Ibrahimovic whose header was superbly saved by the Watford keeper as United cranked up the pressure.
But the visitors were again undone by poor defending as Juan Camillo Zuniga ran into a cut-back by Nordin Amrabat and scored with his first touch a minute after coming on for Capoue.
Fellow substitute Isaac Success then outmuscled Eric Bailly and ran into the box and laid it off for Zuniga, only for the latter to be fouled by Fellaini in the box. Troy Deeney rammed the resulting spot-kick down the centre of United's goal as Watford secured a famous home victory over United after a gap of 3 decades.
Watford 3 (Etienne Capoue, Juan Zuniga, Troy Deeney penalty) beat Manchester United 1 (Marcus Rashford)