The Stamford Bridge outfit are still fighting for two trophies this season, while also attempting to secure a Champions League place by finishing in the top four of the Premier League.
Manchester United pose a huge test to Chelsea's FA Cup ambitions on Sunday, but Cech has insisted that his side are fully focused on earning a result against Steaua Bucharesti on Thursday evening.
The Czech stopper told the club's official website: "We cannot be thinking of Manchester when we have an important Europa League match ahead.
"We need to take it step by step because each game is important for us. The manager has to think into the future but us players, we always concentrate on the one upcoming game."
The 30-year-old has featured 39 times for Chelsea this season.