Manchester United returned from the international break hoping to return to winning ways, but endured a nightmare first half against Watford from which they could not recover.
Ole Gunnar Solskjaer's side could have found themselves behind inside the first 10 minutes, were it not for David De Gea saving Ismaila Sarr's twice-taken penalty, but goals from Joshua King and Sarr ensured a dominant Watford went in 2-0 up at the break.
Substitute Donny van de Beek got United back into the game early in the second half, heading home from close range, and both teams had chances to net again in an open game at both ends.
United's problems continued midway through the second period, though, with Harry Maguire sent off for a second booking, and Joao Pedro's stoppage-time goal clinched victory for the hosts and Emmanuel Dennis rubbed salt into the wound.
It's yet another blow for United's season, and will surely result in more questions being asked about the future of manager Ole Gunnar Solskjaer.
