Pep Guardiola does not want the glow of derby success to cause Manchester City to lose focus in Tuesday's Champions League opener against Borussia Monchengladbach.
City impressed on the way to a 2-1 win over Manchester United at Old Trafford on Saturday and will attempt to extend their 100 per cent record under Guardiola when the Bundesliga side visit the Etihad Stadium.
United came on strong after an error from goalkeeper Claudio Bravo allowed Zlatan Ibrahimovic to get a goal back on the stroke of half-time.
And Guardiola reminded his in-form players there is still plenty of room for improvement, particularly when it comes to taking on elite opposition, at home and abroad.
"We made good things and bad things [at the derby] but it's just three points. Of course we're happy but we have to improve," he told a pre-match news conference.
"We have to improve a lot of things. We are first in the Premier League but the way we have played so far will not be enough to win the Premier League.
"The way we have played in these six games is not good enough to win the Champions League."
Guardiola will welcome Sergio Aguero back from a domestic suspension, with captain Vincent Kompany and midfielder Ilkay Gundogan continuing to build their fitness, but much focus is likely to fall upon Bravo on his home debut following an erratic initial showing in City colours.
"Bravo is so strong," said the ex-Barcelona boss, echoing his post-match backing for the Chile international from the weekend.
"I saw the action of the goal - three or four times after he played with personality. That's what I tried to say after the game.
"I was convinced before the game and after I feel the same. Claudio is going to make mistakes in the future, I'll tell you now - he won't save all the goals. I'm pretty sure of that."
Two players who are unlikely to need a morale boost from their boss are midfielders David Silva and Kevin De Bruyne.
The duo continued superb early season form at Old Trafford, where De Bruyne opened the scoring and Silva schemed inventively throughout.
Guardiola has deployed them centrally as opposed to in wide attacking areas but played down his influence, citing the good fortune of both players being free from the injury issues that plagued them during Manuel Pellegrini's final season in charge.
"When they were fit under Manuel, they were amazing," he added.
"I didn't discover them. I just put them on the pitch in good condition."