Manchester United manager Michael Carrick said it was "worrying" a team of officials came to the conclusion Erling Haaland's winner should stand as 10-man Manchester City stunned Old Trafford on Sunday.
The only goal was originally ruled offside, but that decision was reversed after a lengthy VAR review.
Enzo Fernandez was in an offside position as he attempted to head home before the ball reached Haaland, but the Argentine was deemed not to be interfering with play.
"It's worrying, if that's really how it is, if that's how the game is seen by those who are officiating it," said Carrick.
"I just don't get it, I really don't get it, I can't understand them."
Lisandro Martinez was the United defender at the centre of the controversy.
Martinez said he was clearly impacted by the presence of his international teammate Fernandez and branded the City goal an "injustice".
"I went to him because he was in front of me. That's why Haaland was free at the back," Martinez told Sky Sports.
"Five or six people (officials) doing this kind of mistake in the Premier League is unacceptable.
"We have to go home with this injustice."
United have taken just four points from their opening four league games to already fall eight points behind defending champions Arsenal and City.
After a League Cup clash against Brighton and a visit to Fulham next weekend, Carrick will have a three-week international break to reflect on a poor start but said only a return to winning ways will ease the mounting pressure on his shoulders.
"We haven't got as many points as we would have liked at this point, for sure, there's no getting away from that," added the United boss.
"But we don't need a break or a restart, we've just got to move on and win games."