Ronaldo, meanwhile, looked far from impressed after it emerged that he wouldn’t be coming on to make an impact as Casemiro, Anthony Martial, Victor Lindelof, Luke Shaw and Fred earned minutes.

Ronaldo’s reaction after it emerged that he wouldn’t be brought on. Image credit: Sky SportsIn terms of the result, goals from Erling Haaland [3] and Phil Foden [3] sealed all three points for the defending Premier League champions, while United struggled to withstand City’s attacking threat.

After the full-time whistle, a furious Morgan slammed Erik ten Hag after the former Ajax boss claimed Ronaldo was not brought on at 4-0 down “out of respect for his big career”.

He added: “The other thing was the advantage I could bring Anthony Martial, he needs the minutes but I don’t want to point it out like that.”

Moments later and Morgan tweeted: “Imagine benching @Cristiano for Utd’s biggest game of the season, then using five other subs as they’re hammered into oblivion, and then claiming you did it ‘out of respect’ for him?

“Ten Hag is an arrogant deluded twerp and the way he’s treating Ronaldo is disgraceful.”

In the aftermath of Sunday’s result, Roy Keane also accused Manchester United of “disrespecting” Cristiano Ronaldo.

“Even today, could he have brought him on? Of course, he could’ve brought him on. So what if you’re four nil down. If you look at his goalscoring record, he has as good a chance as anyone of putting the ball in the back of the net,” Keane said.

“People are obsessed with the pressing side of the game… If you put the ball in the right areas, he’ll score goals.”

“Man United are showing disrespect to Ronaldo,” he added. “I think he should’ve been let go before the transfer window [closed].

“I think the manager holding onto him, ok, you say you need options, but if you don’t hold onto Ronaldo to sit on the bench He’s one of the greatest players ever, he had options, this idea that he had no options is rubbish. He did have options, four or five very good options.”

Keane continued: “Ok, today, the manager brought Martial on, who scored two, so yeah that’s justified. But generally speaking, the bigger picture, he’s not going to play Ronaldo, we know that.

“He’s played in one or two European games, it’s just going to get uglier as the season goes on. Ok, Ronaldo’s motivated with the World Cup coming up. But if he’s sitting on the bench for Man United week in week out, it’s not good.”