Michael Olise scored a brace of goals as Crystal Palace completed a league double over Manchester United for the first time in its history with a thumping 4-0 victory at Selhurst Park on Monday that will add to the pressure on Erik ten Hag.
A makeshift United defence that included Casemiro at centre-back was easily picked apart by Palace on several occasions as Jean-Philippe Mateta and Tyrick Mitchell were also on the scoresheet in the impressive win.
United remains in eighth place with 54 points from 35 games, two points behind Newcastle United in sixth, with its hopes of European football next season fading fast.
Palace is still in 14th with 43 points from 36 matches.
United had several injury absentees and was without Bruno Fernandes, the first time in his 230-game Old Trafford career he has missed a match with injury, but the ease with which the visitors were beaten will be a huge concern for everyone at the club.
It is the first time in the Premier League era United has lost 13 games in a season and the scoreline might have been worse.
Palace has found its groove under new manager Oliver Glasner, but United is limping to the end of a season that cannot finish soon enough for Ten Hag.
The home side took the lead inside 12 minutes and it was far too easy. Olise collected a throw and evaded a limp challenge from Casemiro, and with no United player attempting to close him down, was able to unleash a low shot from just inside the box.
United had the ball in the back of the net from Casemiro's header, but the effort was ruled out after contact from Rasmus Hojlund on Palace goalkeeper Dean Henderson.
It was 2-0 to the home side five minutes before the break as Mateta breezed past United defender Jonny Evans and thrashed the ball into the net for a ninth goal in 11 games since the arrival of Glasner in February.
The striker had scored 11 goals in his previous 80 games for Palace before that.
United's makeshift defence was struggling to contain the movement of the hosts and when Diogo Dalot failed to deal with a ball to the back post, Mitchell had a tap-in with home players queuing up to score.
Olise's second goal added more salt to the wound and it could have been worse for the visitors as Odsonne Edouard saw his shot come back off the woodwork late on.
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Reuters