Striker Didier Drogba has warned Chelsea's title rivals to be ready for a backlash from the Blues as they prepare for three games that could define their season.
Chelsea have won just two games out of the last eight in all competitions and they now face Tottenham at White Hart Lane on Sunday, followed by Manchester United at home and Arsenal at the Emirates.
And Drogba insists that victories over all three could turn their season around, saying: "Obviously these three games are not coming at the right time for us, but maybe these matches will change the situation we're in now if we win them. It's not finished yet."
He added: "It's a difficult moment for us, but this is the kind of thing that can happen to many teams and it's rare for Chelsea to have a period like this and I hope it's going to get better."
Chelsea created little against a weakened Marseille team as they lost 1-0 in the Champions League on Wednesday night, and apart from two rejected first-half penalty appeals they produced nothing to worry Marseille's defence or their English title rivals.
"This was another very disappointing defeat," added Drogba. "We conceded in the last minutes of the game.
"It is difficult to take. The good thing is we have still qualified and finished top of the group."