Watford thrashed Manchester United 4-1 at Vicarage Road to pile even more pressure on the under-fire Ole Gunnar Solskjaer.
Joshua King and Ismaila Sarr had given Watford a thoroughly deserved 2-0 lead at half-time, before Donny van de Beek’s second ever goal in English football gave the visitors a sniff of a chance.
But a late United collapse, following on from a red card for Harry Maguire after a poorly judged tackle while already on a yellow card, and stoppage time goals from Joao Pedro and Emmanuel Dennis ensures the Old Trafford hierarchy have a huge decision to make.
Even before King fired home from close range just under half an hour into the contest, Watford had already squandered a glorious chance to go ahead.
The Hornets were awarded a penalty when Scott McTominay clumsily upended the Norwegian, only for Sarr to see his effort saved by David de Gea. Kiko Femenia followed it in and lashed the ball into the net, but he was encroaching in the penalty area before the kick was taken. That meant Sarr was given the chance to convert a second time, but again De Gea parried the ball away.
United were extremely poor in the first half, failing to put much of anything together going forward and all over the place defensively. It meant Watford were well worth their second when Dennis found Sarr to fire in a powerful effort before the break.
Van de Beek, on at half-time, make a difference for United and scored within five minutes. Cristiano Ronaldo also had chances and even had the ball in the net at 2-1, only to see the offside flag go up.
What could have been a nervy final few minutes for Claudio Ranieri’s Hornets turned into a party when first Pedro and then Dennis fired in late goals to seal a famous win.
Watford player ratings
1. Goalkeeper & defenders
Ben Foster (GK) - 7/10 - Made two key saves that preserved Watford's lead at both 1-0 and 2-1. Not otherwise tested over much.
Kiko Femenia (RB) - 7/10 - Just slightly too eager to follow in the first penalty rebound. Always willing to get forward and got an assist.
Craig Cathcart (CB) - 6/10 - Would have expected a tougher day.
Nicolas Nkoulou (CB) - 6/10 - Solid performance until he was forced off with an injury with over half an hour still to play.
Adam Masina (LB) - 7/10 - Did well defensively to limit United's wide threats.
Moussa Sissoko (DM) - 7/10 - Patrolled the base of the midfield well.
Imran Louza (CM) - 7/10 - Hasn't played a great deal of football since moving to England but gave a strong account of himself here.
Tom Cleverley (CM) - 7/10 - Looked eager to prove something against his former club with tenacious midfield pressing.
Ismaila Sarr (RW) - 8/10 - Twice denied by De Gea from the penalty spot, although he made up for that by smashing home Watford's second.
Joshua King (ST) - 8/10 - A real threat for the Hornets. Could have scored one before he doubled his team's lead before half-time.
Emmanuel Dennis (LW) - 8/10 - Struck up some good interplay with his attacking colleagues. Assisted the opener for King and got the fourth.
William Troost-Ekong (CB) - 6/10 - Like for like replacement for Nkoulou.
Cucho Hernandez (RW) - 6/10 - Good minutes under his belt.
Joao Pedro (ST) - 7/10 - Worked hard and well worth his goal.
Man Utd player ratings
5. Goalkeeper & defenders
David de Gea (GK) - 7/10 - Saved twice from the penalty spot, but his efforts proved to be in vain because the team in front of him was so limp.
Aaron Wan-Bissaka (RB) - 4/10 - Not sharp enough at all. Particularly poor when the first goal went in.
Victor Lindelof (CB) - 4/10 - Fighting a losing battle. Not good enough.
Harry Maguire (CB) - 2/10 - Gave the impression he didn't understand even basic defending or positioning. Then he was sent off.
Luke Shaw (LB) - 5/10 - Substituted in the second half after a knock to the head after only recently returning from a concussion.
Scott McTominay (CM) - 4/10 - Giving away the penalty was clumsy more than anything. Only just back from illness and withdrawn early.
Nemanja Matic (CM) - 4/10 - Couldn't get a foothold in midfield and didn't offer the back four anything like enough protection.
Bruno Fernandes (AM) - 3/10 - His failed clearance in the build up to the penalty was very poor. So was his non-existent response to following in the rebound - but he got lucky with that one. Otherwise very disappointing.
Jadon Sancho (RW) - 6/10 - Sparked into life after the interval. Some of his delivery to Ronaldo was really good and a potential sign of things to come.
Cristiano Ronaldo (ST) - 6/10 - Had to come deep to try and get into the game in the first half. Got the assist for Van de Beek and went close with other efforts, including a goal that was flagged offside.
Marcus Rashford (LW) - 5/10 - Had United's only chance of the first half. Still probably lacking match fitness. Off after 45 minutes.
Anthony Martial (LW) - 4/10 - Had looked okay but sloppily gave the ball away that led to Watford scoring their killer third.
Donny van de Beek (CM) - 7/10 - Not the circumstances he would have wanted to come on in, but scored five minutes into the second half and made such a positive difference. Has to start the next game.
Diogo Dalot (LB) - 5/10 - Late swap at left-back for Shaw.
Jesse Lingard (RW) - N/A - Way too late for him to do anything.