However, Liverpool could climb above them if they win against Tottenham Hotspur at Anfield on Sunday, while Manchester City in third have two games in hand over the London outfit.
"I think it is now impossible to win the title," Mourinho told Sky Sports News. "We depend too much on other results. With what happened two weekends ago (losing to Aston Villa) and today, it is too much now and we depend on too many results.
"Of course, with my mentality, I want to try and win every game. The main objective is to finish in the top four. The second objective is to finish in the top three, which is also important.
"Since the beginning of the season, I am just trying to win without thinking too much about positions, and about points."
Chelsea last won the league title in 2009-10.