Manchester United were handed a reality check in their 6-3 thrashing at Manchester City but are ready to bounce back after learning a lesson, manager Erik ten Hag said ahead of Thursday's Europa League group stage game at Omonia Nicosia.
A run of four successive league wins under Ten Hag had promised better times ahead but United were brought firmly back down to earth after a humbling afternoon against Pep Guardiola's City.
"It was a reality check, and we have to learn from it and carry on," Ten Hag told reporters on Wednesday. "It was a difficult day... You take respect of the opponent, but we will stick to our philosophy and principles.
"You will have setbacks. We beat Arsenal, we beat Liverpool. On Sunday, we had a bad day at the office. City were better, we have to accept that. But we can't accept our unacceptable performance.
"We can get a lot of confidence from beating Arsenal and Liverpool, but now we get a reality check from Man City. So thank you for the lesson, Pep and City. We have to understand, we have to do things much better."
Ten Hag refuted suggestions of any relation between Cristiano Ronaldo not being called off the bench in the Manchester derby and the Portuguese forward's future at the club.
Ronaldo, in his second spell at United, has started only one league game this season and was linked with a move away during the summer transfer window but Ten Hag said he remains committed to the club.
"When we were 4-0 down or 6-1 down, I said I didn't bring him on out of respect. That has no connection with his future at the club," Ten Hag said. "I don't see he is unhappy. He is training well and enjoying being here.
"He's not happy that he wasn't playing Sunday, don't get me wrong. Of course, he wants to play and he's pissed off when he's not playing."
United have begun their Europa League campaign with a win and a defeat from their first two Group E games. They are second with three points, three behind leaders Real Sociedad, while Omonia are bottom and yet to pick up a point.
Ten Hag's side will be without Raphael Varane for Thursday's trip to Cyprus after the centre back sustained an ankle injury in Sunday's defeat to City. Captain Harry Maguire as well as Aaron Wan-Bissaka and Donny van de Beek are also unavailable.