Manchester United boss Erik ten Hag has thanked Manchester City and their manager Pep Guardiola for providing a "lesson" in Sunday's Manchester derby.
The Red Devils entered the clash off the back of four straight wins in the Premier League, but they suffered a 6-3 defeat to the reigning English champions at Etihad Stadium.
Man City led 4-0 at the interval and 6-1 in the 73rd minute, before Anthony Martial netted a late brace for the visitors to make it a more respectable scoreline.
Ten Hag has said that there will always be "setbacks" in the process, and the Dutchman is confident that his side will have learned a lot from the difficult afternoon in Manchester.
"I know when you are in a process, it will not go only [your way]. You will have setbacks, and we beat the number one in the league [Arsenal], we beat Liverpool. On Sunday, we had a bad day at the office and we got beat," Ten Hag told reporters on Wednesday afternoon.
"And in this moment, on that day, City were better. We have to accept that. But what we can't accept is our performance. That was unacceptable.
"That's what you always do, that you have respect for the opponent. But we will stick to our philosophy. We will stick to our rules and principles. But the tactics, sometimes in your tactics, sometimes to surprise your opponents you have to bring something different and people do, also for the future.
"But I think what's good, and I think we can have a lot of confidence about this; when you beat Arsenal, when you beat Liverpool, and now we get a reality check with Man City.
"So we know that we have to step up. Thank you for the lesson, from Pep and City, but we will take that and we have to understand that we have to do things much better."
Man United have since switched their attention to the Europa League, with the team heading to Cyprus to take on Omonia in their third game in this season's competition.
The Red Devils are currently second in Group E, having picked up three points from two matches, losing to Real Sociedad in their opener before beating Sheriff Tiraspol last time out.
Man United now have a double-header against Omonia before welcoming Sheriff and travelling to Real Sociedad, with the group stage finishing in early November due to the 2022 World Cup.
The 20-time English champions will be back in Premier League action away to Everton on Sunday night, while they will also take on Newcastle United, Tottenham Hotspur, Chelsea and West Ham United in the league before the end of October.
A total of 12 points from seven games has left Ten Hag's side in sixth spot in the Premier League table, two points behind fourth-placed Brighton & Hove Albion and nine behind leaders Arsenal, albeit with a game in hand on the Gunners.
