Manager Avram Grant insisted that his side are well and truly in the Premier League title race, following a hard-fought 1-0 victory at Sunderland.
A John Terry header proved decisive at the Stadium of Light, with the Blues now just three points behind Manchester United and Arsenal in the race for the crown.
Grant commented: "If there is even one in the club who does not believe, he should not be in football.
"I am positive and very optimistic by nature, but if I was in a situation where I did not believe, I would be looking for another job.
"The belief was here maybe from the second week I was here. We have shown there is a reason why we can believe in this. We believe, even if sometimes we lose games.
"Chelsea wants to be a big club and sometimes even people from outside need to know Chelsea is a big club. When we lose a game, it makes us stronger, it does not make us weaker.
"You saw the response after the Carling Cup and the FA Cup, it was not easy because we were all disappointed, but we are not changing our way because we lose a game.
"I am happy with the result, of course. It is not easy to play here. Sunderland are fighting for their lives and they fought very, very well.
"We started the game very well. We scored a goal and could have scored more, but then in the second half it was more difficult and Sunderland were very dangerous."