Manchester City can learn important lessons from Sunday's 2-0 derby defeat to Manchester United, according to Pep Guardiola.
Bruno Fernandes' second-minute penalty and a fine Luke Shaw effort shortly into the second half gave Ole Gunnar Solskjaer a third consecutive victory at the Etihad Stadium.
It brought City's record-breaking run of 21 consecutive wins in all competitions to a shuddering halt, although their lead over their neighbours at the Premier League summit is still a healthy 11 points.
With ambitions to taste elusive success in Europe this season, Guardiola acknowledged his in-form side might have been handed a timely reality check.
"Today we are going to talk about it because we lost and that is the news," he said. "But the news is 21 victories in a row. This is the news.
"This result is going to help us a lot to know how difficult it is.
"We knew it but sometimes you have to not win one game to realise. The important one is the next one.
"There are still many games to play, 30 points to play for and in the next game we have the opportunity to do it."
City are back in action against Southampton on Wednesday and Guardiola did not feel his players did too much wrong in a game where Gabriel Jesus' clumsy challenge on Anthony Martial inside the first minute left them fighting an uphill battle.
"We played a fantastic game, a lot of shots," he said. "Starting in that way punished us a lot against a team who, for many years, defends sitting back for the counter-attack.
"They made incredible high pressing, but when you break this action they defend far back.
"On the counter-attack they are so fast. Like Ole Gunnar Solskjaer said, the history of Man United is about the counter-attack, the pace.
"We played good, apart from the first 10 minutes. Fortunately we could not be clinical up front and congratulations to United."
Rodri rattled the crossbar shortly before Shaw extended United's advantage – something Guardiola conceded was a pivotal passage in the match.
"It's tough. We had a shot against the crossbar from Rodri and after they did the goal. That's football, you have to overcome," he added.
"After the goal there were five minutes where we were not [good] but after we take the game [to United] and we were really good at the normal level that we are playing.
"We played to continue [the run], we played to do it and it will be a good lesson not to concede the goals we conceded.
"When we lost here to Leicester 5-2, we conceded three penalties. Here, another penalty. It was not a dangerous situation [before the foul], always you have the keeper to save it.
"Apart from this, we played really well. Even after 2-0 we played really well. We conceded a few counter-attacks, but it is normal.
"United are really good at this. The moment we start to attack and they defend deep they are a fantastic, incredible team."