Diego Costa's header was cancelled out by Dusan Tadic's penalty as Chelsea were unable to take full advantage of Manchester City's defeat to Burnley on Saturday despite starting well.
With Chelsea six points clear and having a game in hand on City, Mourinho told reporters: "I'm not happy with the result but I'm happy with the situation, the six-point lead.
"Even knowing a point would give us a six-point lead we played to win in the last 15 minutes of the game."
Mourinho saw Eden Hazard, Willian and Loic Remy all go close late on only to be denied by an impressive Fraser Forster performance at Stamford Bridge.
"We started well but the penalty changed the rest of the first half. We stopped playing and made some mistakes," the Chelsea boss added.
"When Ramires came on we killed their counter-attack and had complete control of the game.
"We had a lead of five points and now we have a lead of six points with one less game to play."
