Manchester City manager Roberto Mancini believes that his side need to improve, despite moving to the top of the Premier League table with a 4-1 win at home to Aston Villa.
Goals from Mario Balotelli, Adam Johnson, Vincent Kompany and James Milner have lifted City two points clear of local rivals Manchester United.
"I think that we have started the season very well," said Mancini. "We knew that this week would be hard because we play Villa, Villarreal and after that we have the derby, and I think our minds are very busy.
"We have played only eight games, there are still another 30. We should be happy to go to Old Trafford on the top, but we should understand that the championship will be long and this position will change every week.
"We will fight until the end for the title. We have started very well, we have won a lot of games, but we need to improve more."
The Blues next host Villarreal in the Champions League on Tuesday, before they visit Old Trafford to take on Manchester United five days later.
