Gary Neville described Manchester United's derby defeat as a "bad day" for Michael Carrick's side, with the pressure increasing after failing to beat 10-man Manchester City at Old Trafford.

United failed to make their numerical advantage count after Phil Foden was sent off early on in the first half, losing 1-0 to Erling Haaland's controversial winner.

Refereeing body Pro Ref admitted an error in awarding Manchester City's winner just hours after the final whistle.

They revealed it had made contact with Manchester United to acknowledge an "error of judgment" and that the VAR "should have recommended an on-field review" with Enzo Fernandez, in an offside position, potentially impacting play.

Sky Sports News understands United have received an apology over the incorrect VAR decision.

Despite contention around the goal, Neville said the failure to beat 10-man City was a major concern, particularly given United's struggles to manage the game.

"Michael Carrick can be angry about the goal but he should also be angry about the performance," Neville said on the Gary Neville Podcast.

"It was an awful last 10 minutes from an experience perspective for Manchester United because that's where you think, to be fair, you throw the kitchen sink at it, and you're building the crowd up and the pressure up and it's a pressure cooker and you get a goal."

Neville believes Sunday's defeat also highlighted a wider problem with United's apparent inability to navigate matches after an opponent has a player sent off.

United have now lost three games in the last year to 10 men, including a 1-0 defeat to Everton last season following Idrissa Gana Gueye's red card at Old Trafford.

The result leaves United with just four points from four games, matching the club's worst start to a Premier League season. Carrick's record after four games is identical to Ruben Amorim's at this point last season.

Neville acknowledges that it is still early in the season but warns that there are already concerning signs, with the pressure continuing to increase on Carrick.

"It was a bad day for Manchester United, it really was," he said.

"You're losing a derby, it's a shocking day anyway. I've lost derbies myself, it's awful, but then to not score a goal against 10 men is not what I expected today. I expected goals from Manchester United.

"It is early but there are some concerning signs. They're not playing well in matches and they're also struggling in matches.

"Even the game against Ipswich; Ipswich were good for 55 minutes and caused big problems. They could have scored two or three, so there's some questions building."

United's next game is away to Fulham on Sunday, live on Sky Sports, and Neville believes the pressure will increase on Carrick.

"Next Sunday against Fulham, that becomes a real pressure game now because obviously Fulham have not started the season that well," said Neville.