The former Barcelona coach wants to see an improvement next week after a disappointing display against Wolfsburg at the Allianz Arena on Saturday afternoon
The Catalan coach was not impressed with the Bavarians' performance in Saturday's Bundesliga victory over Wolfsburg, with the reigning champions only scraping home thanks to Thomas Muller's goal midway through the second half.
With Bayern facing trips to the Etihad and the BayArena in the next week, Guardiola is in no doubt that his players will have to give more if they are to maintain their current unbeaten run.
"We won, but we have to improve a lot," the former Barcelona boss is quoted as saying by his club's official website.
"We will analyse the game. But I am sure that we will put in better performances in Manchester [on Wednesday] and Leverkusen [on Saturday]."
Meanwhile, match winner Muller admitted that Bayern had not played anywhere near their best at the Allianz Arena, though he felt that their opponents deserved credit for making life difficult for them.
"Wolfsburg gave us nothing, so it was not easy," the attacking midfielder conceded. "They basically went man-for-man all over the pitch and that caused us some problems.
"We can be happy that we won. But it was hard earned.
"Our goal was excellently worked, though, and I am pleased that I am now off the mark in the Bundesliga."
Bayern's eagerly-awaited Group D clash with City is scheduled to kick off at 20:45CET.