Erling Haaland's contentious winner earned 10-man Manchester City a derby win over rivals United at Old Trafford - after Phil Foden's controversial first-half red card.
City have now joined Arsenal as Premier League title race pace setters with maximum points from four games - but their winning goal against Man Utd was given via an "error in judgement" by the officials.
In the build-up to Haaland's winner, Enzo Fernandez looked like he impacted play when clearly in an offside position - but the goal was not ruled out. Refereeing body Pro Ref admitted their mistake in awarding the goal three hours after the full-time whistle.
City, however, will feel justice was done after their job became much harder when Foden was given his marching orders earlier. A tepid first half of the 199th Manchester derby was dominated by Foden's shock sending-off.
After United captain Bruno Fernandes kicked the ball into his midriff, Foden reacted by kicking out at the Portuguese. "VAR has described it as a kick with both feet into the stomach," said Gary Neville on co-commentary.
- As it happened | Teams | Stats | Watch FREE PL highlights
- Latest news and rumours: Man Utd | Man City
- Got Sky? Watch Premier League games LIVE on your phone📱
- Not got Sky? Latest Sky Sports deals or stream Premier League games with no contract📺
Whether there was enough contact from Foden to cross the violent conduct threshold will be debated. Whether Fernandes should have also seen red for kicking out at Foden first will also be talked about.
Despite the man advantage, United struggled to use their dominance to full effect. They did hit the post twice through Marcus Rashford and Kobbie Mainoo - but when Haaland is on the other team, City always have a chance.
That came true as he tapped home at the back post, yet the offside flag went up. The semi-automated offside technology ruled Haaland onside so the goal was given - but Fernandez being clearly offside and trying to get on the end of the same cross was also approved by VAR.
This content is provided by Twitter, which may be using cookies and other technologies. To show you this content, we need your permission to use cookies. You can use the buttons below to amend your preferences to enable Twitter cookies or to allow those cookies just once. You can change your settings at any time via the Privacy Options.
Unfortunately we have been unable to verify if you have consented to Twitter cookies. To view this content you can use the button below to allow Twitter cookies for this session only.
The Premier League Match Centre claimed the goal was allowed because Fernandez did not touch the ball - when the rules state that is not necessarily relevant, as impacting the play is the crucial line in the rulebook.
While the conversation over the Foden red card and the Haaland winner will go on, City will see themselves as real contenders for the title after a gutsy display with 10 men.
United, who saw Bryan Mbeumo denied a late leveller by a stunning Gianluigi Donnarumma save, will ask themselves why they didn't have the quality to hurt a transitional City with an extra man.
WATCH: The two big calls
Please use Chrome browser for a more accessible video player
Please use Chrome browser for a more accessible video player
The key moments from Old Trafford
23: RED CARD! A slow-starting derby explodes into life as Foden is sent off for kicking two feet out at Fernandes.
45+1: OFF THE POST! Man Utd struggle to fashion chances after the sending-off, but Rashford's 28-yard free-kick comes off the foot of the woodwork.
51: OFF THE POST AGAIN! Mainoo's curling effort beats Donnarumma but lands on the foot of the post.
60: GOAL! Haaland taps home at the far post but is flagged offside. After a lengthy check, Haaland is deemed onside by the semi-automated offside technology - but was Fernandez offside in the build-up?
68: OFF THE POST! Fernandez nearly doubles City's lead but his drive is tipped onto the post by Senne Lammens.
86: WIDE! Harry Maguire has United's best chance of a leveller but he nods wide at a corner.
90+5: WHAT A SAVE! Donnarumma denies Mbeumo late equaliser with amazing stop!
Man Utd furious with Haaland winner standing
Please use Chrome browser for a more accessible video player
Manchester United defender Lisandro Martinez to Sky Sports: "I think [Fernandez] was offside. What I can't understand is the rules. He was there! I went to him because he was in front of me. That's why Haaland was free at the back.
"I want to be calm but it is so hard. Every season the officials come to our club and spend an hour explaining the rules and they look so confident with that.
"Then after, five or six people (officials) doing this kind of mistake in the Premier League is unacceptable. We have to go home with this injustice."
Man Utd head coach Michael Carrick: "The explanation I got was that he wasn't interfering with play. I just don't get it, I really don't get it.
"If that's how the rules are interpreted, that you're not interfering with play because you've thrown yourself at the ball six yards from goal and pretty much nearly touched it, which then Licha [Martinez] has to react from.
"On top of that, the [offside] was a bit dubious - where we drew the line to start with. It's worrying if that's really how the game is seen by those who are officiating it."
Maresca: Fernandes should have been sent off on top of Foden!
Man City head coach Enzo Maresca:
"I think Phil Foden's red card is a red card, but I also think that in the same action it's a red card for Bruno Fernandes.
"I reviewed the action immediately after the red card on the bench. And it's a clear red card for Phil, because it's a reaction.
"But you can also see in the same action Bruno's intention. So for me, yes, it's a red card for Phil, but it's also a red card for Bruno.
On Man City's winner: "I think Erling was onside and Enzo doesn't interfere with the action."
How the pundits reacted to Foden red card
Please use Chrome browser for a more accessible video player
Roy Keane: "Foden does react. The strange thing is that Fernandes gives a kick...for me, he is the one who is violent here. I don't think it's a red card for Foden, l really don't."
Micah Richards: "Fernandes catches him! I don't agree with Foden's response, but it's Fernandes who started it."
Gary Neville: "It looks like Foden has reacted. He has kicked him in the stomach. You are not going to get away with that."
What the result means and next fixtures...
- Man Utd fixtures
- Man City fixtures
- Premier League fixtures
Rate the players!
Monterosa
This content is provided by Monterosa, which may be using cookies and other technologies. To show you this content, we need your permission to use cookies. You can use the buttons below to amend your preferences to enable Monterosa cookies or to allow those cookies just once. You can change your settings at any time via the Privacy Options.
Unfortunately we have been unable to verify if you have consented to Monterosa cookies. To view this content you can use the button below to allow Monterosa cookies for this session only.