Victor Lindelof says Manchester United could not capitalise on Manchester City's nervousness in yesterday's derby.
An Anthony Martial penalty in the second half brought the scores to 2-1 and could have possibly changed the momentum in United's favour.
However, City quickly took control of the game once again and eventually sealed victory through Ilkay Gundogan.
Lindelof told MUTV: "After that goal [from Martial] they were quite nervous and it felt like we could have scored another goal, but they scored a third goal instead, so it happens in football, but we are very, very disappointed, because we felt that we could have scored a second goal and got a better result.
"We had quite a lot of possession, but we didn't really come in behind their defensive line into their last third of the pitch. But we tried and, like I said, it felt like we could've hurt them more.
"I think we started the game, the first 15 minutes, quite badly.
"They had a lot of possession and we didn't do so much, but after their goal we started to play a little bit and we made it harder for them.
"After we scored after our goal we could have been a bit more aggressive and tried a little bit more but we lost and we're sad about that."