Leroy Sane opened the scoring just before halftime at the Etihad Stadium, before a brace from Raheem Sterling and further strikes from Sergio Aguero and Fabian Delph wrapped it up in the second half.
“We started good, in the first five or 10 minutes we created two or three clear chances, but after that we were not good,” he said. “The ball should be moved and we didn’t move it.
“The last 10 minutes of the first half we started to play good again and it helped a lot to score the first goal before half-time. The second half we were at the level of the last few weeks.
“Last season we had a lot of problems at home winning games. That’s why we dropped our competition in the Premier League.
“That’s why the last two games are so important – winning 5-0 against Liverpool and Crystal Palace – for our confidence and for the other games when we come back from the international break.”
City, who currently lead the Premier League standings, host Ukrainian side Shakhtar Donetsk in the Champions League on Tuesday, and face Chelsea at Stamford Bridge next weekend.