David Silva believes Manchester City need to beat Chelsea on Sunday to prevent Jose Mourinho's team from opening an insurmountable gap at the top of the Premier League.
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Defending champions City have dropped five points in their last two games after losing to Stoke and drawing with Arsenal.
And defeat at the Etihad Stadium would leave them eight points behind Chelsea, who have a 100 percent record in the Premier League this season.
Silva, speaking to lead the Anfi campaign "A new home for Bailey," said: "It is early in the season, there is a long way to go, and we know in the Premier League that anything can happen. But we need to win on Sunday because otherwise the gap would be getting too big between the clubs."
Three of the World Cup winner's Spain teammates are in the Chelsea squad, with Cesar Azpilicueta being joined by summer signings Cesc Fabregas and Diego Costa this summer.
And midfielder Silva said he is in contact with the two newcomers, adding: "Sometimes we exchange texts. I have a very good relationship with both players. I have known Fabregas since we were 16 years old and were in the Spanish youth squads together. I think Chelsea have made some fantastic signings this summer but our friendship will be set aside because we are going out on Sunday to win.
"I'm looking forward to facing Cesc but in pretty much every game now I seem to be up against a Spanish teammate -- when we play Arsenal it's Santi [Cazorla] or when it's United it will be Juan Mata."
Both Fabregas and Costa have made fine starts to the season with the midfielder recording six assists and the striker setting a Premier League record with his prolific start.
"Diego has made a huge impact," Silva said. "He's scored seven times so far so that speaks for itself. That's very important for Chelsea but not that good for us. But we've got a good defence and I believe we can stop him on Sunday."
Costa, who joined from Atletico Madrid, has settled straight into English football and Silva added: "It is not easy to adapt but he has clearly done it very quickly. Fabregas, of course, knew the Premier League before, from his time at Arsenal. Some players adapt quicker than others but it is never easy."