Manchester City manager Roberto Mancini says that his team must improve, despite beating Wigan Athletic 3-0 on Saturday.
Carlos Tevez missed a first half penalty at the Etihad Stadium, but it counted for little as Sergio Aguero's hat-trick claimed the three points.
The win took the Blues to the top of the league for a matter of hours, before local rivals Manchester United went ahead of them on goal difference after their 5-0 win at Bolton.
"We had 15 chances in the first half and we scored only one goal - this is a problem because the game can change any moment," said Mancini.
"Next time it's better if we close out the game in the first half. We need to improve because we have started the season very well but the season will be long.
"If we want to arrive at the end of the season still at the top we need to improve."
City take their Champions League bow on Wednesday when they host Napoli in their first group game.
