Casemiro played "like he was 45" and Harry Maguire deserves to start - according to one devastating analysis of Manchester United's 3-1 home loss against Brighton.
Ex-England striker Gabby Agbonlahor claimed the Red Devils were so dire that the Seagulls treated it "like a training-ground game" and had a "stroll in the park".
Brighton's fourth Prem win in a row against United means Erik ten Hag's men have lost three of their opening five league games.
And Red Devils' fans booed when the Dutchman replaced new striker Rasmus Hojlund with Anthony Martial midway through the second half.
Brighton, however, were already 2-0 up and on top virtually throughout.
Ex-United frontman Danny Welbeck, Pascal Gross and sub Joao Pedro sent the Seagulls soaring into the top four.
And a reply from Casemiro's replacement, Hannibal Mejbri, was little consolation.
Former Aston Villa favourite Agbonlahor was stunned by United's display.
In particular, he slated Casemiro's lack of influence in midfield and the shaky pairing of Lisandro Martinez and Victor Lindelof in central defence.
Agbonlahor told talks Port as cited by Sports Central: "It was a stroll in the park for Brighton... at no time did Brighton ever feel like they couldn't pass it out from the back. "No matter who was pressing, they found it so easy to get through and create chances. This was like a training ground game, especially in the second half. "Casemiro! Casemiro looked like he was 45 running around that midfield. He [Ten Hag] had to bring him off on the 65th minute for Hannibal, a young lad, because he was that bad."
Agbonlahor was also "wound up" by the treatment of Maguire.
The 30-year-old was jeered by Scotland fans and netted an own goal in England's 3-1 friendly victory at Hampden Park last Tuesday.
And Agbonlahor feels Maguire is being harshly dealt with at club level too.
He said: "Let's see the same energy for Lisandro Martinez and Victor Lindelof. "Martinez for the Gross goal, he has tried to make a block, he's got fake-shot by Gross and he's scored in the back of the net. "If that was Harry Maguire, you would not hear the end of it - 'he's terrible, get him out the side'. "Maguire must be looking around that changing room now thinking, 'how am I not getting a chance in this team?' Maguire deserves to be in that team. "Let's see that same energy for Martinez at the back, for Casemiro, who can't get around the pitch, not just pick on Maguire.".