Manchester United head coach Erik ten Hag has said that the penalty Manchester City were awarded during the Manchester derby 'changed the game'.
The Citizens were awarded a first-half penalty at Old Trafford when Rasmus Hojlund was adjudged to have fouled Rodri inside the box when the Spaniard was attempting to reach a cross.
The referee did not initially point to the spot, but after being advised by VAR, the spot kick was given, and Erling Haaland stepped up to make it 1-0 to the treble winners.
Haaland then netted a second for Pep Guardiola's side in the 49th minute, before Phil Foden made it 3-0 to the visitors in the 80th minute, with Man City dominant in the second period.
Ten Hag said that he was pleased with his team's first-half performance but admitted that the match ran away from the Red Devils in the second period after they conceded a second.
"The first half we played very good, we defended very well. We had good breaks, good opportunities but we could have taken more benefit. Then the penalty changes the game," Ten Hag told BBC Sport.
"We had to go offensive in the second half, we wanted to be more compact. We know they would press us, go high and go direct.
"The second goal [took the match away from us]. It came too early and then we're making the wrong decisions. We spoke about not pressing the keepers when it was not possible.
"The first half I think things went the way we wanted. The second half, at 2-0, you have to go against them out of shape and when you don't they will find the spare man. We have to be better organised.
"We are down, but we played a good game first half. We will be disappointed and annoyed, but tomorrow we will be there."
Ten Hag was also asked about his substitutions, with Mason Mount introduced for Sofyan Amrabat at the interval, before Alejandro Garnacho came on for Hojlund in the 73rd minute.
Antony and Anthony Martial were then brought on in the latter stages when Man United were 3-0 down.
"You try to get more offensive and you see we worked very hard and brought in new energy, but it was impossible at that point, 3-0 down with five minutes left to play," the manager added.
Man United will be bidding to bounce back from the defeat when they host Newcastle United in the EFL Cup on Wednesday night before travelling to Fulham in the Premier League next weekend.
