"Today I realised – I already knew it but when you experience it yourself it's better – why Sheffield (United) are in the position they are in and didn't lose one game away," said Guardiola.

"It was an incredibly tough game because we played after less than 48 hours one of the most physical teams in the Premier League and we won it so a big compliment for the team again."

Guardiola drafted in teenage defender Eric Garcia for his first Premier League start and, with Claudio Bravo deputising for the suspended Ederson, City looked uncertain in defence as United pushed forward in the early going.

They were grateful to see Mousset ruled marginally offside by VAR after he capped a swift counter-attack half an hour in – another entry on the list of contentious offside decisions this weekend.

"Press play," Wilder said. "I've said it all along. The percentages we are looking at are not big enough. It must be eight or nine goals this weekend. Look at (Norwich's Teemu) Pukki (against Aston Villa), a fantastic finish. The lines are blurred...

"We had a close up of that and the first goal. I just think with these things, there's no conclusive evidence, blurred lines and different angles. There needs to be a more clear way of defining it."

And United were fuming with the officials again after Kavanagh appeared to get in John Fleck's way just as De Bruyne was playing the decisive pass to Aguero for City's opener.

A new rule brought in this summer allows for a drop ball to be awarded if the ball hits the referee at a key moment, but does not legislate for obstruction.

"It was a game-changer, no doubt," Wilder said. "I'm not saying we'd have gone on to win it, but the shape of the team was good. We were not going to come and make it easy.

"It affected the game. (Kavanagh) invited me in after the game and we had a private conversation, he was very open and honest. Whether the PGMOL say anything, that's up to them. I'll keep it between you and me but put two and two together and you'll get the answer.

"I believe if he blows up there wouldn't be a big debate."

It did indeed prove to be a game-changer, with City taking control of the game from that point on, making sure of the win through De Bruyne's 82nd-minute strike, even if there was time for United substitute Billy Sharp to head against a post.

With Liverpool 14 points clear Guardiola has already dismissed his side's title chances and did so again after the match, but said City will not stop battling this season.

"We must prepare, play better, be as close as possible, play the knock-outs and prepare for next season," he said.

"Next season we will be here and hopefully we can do better."