Antonio Conte’s men are six points clear at the top after 17 fixtures, 13 ahead of United.
Four of their last six victories have been 1-0 wins and they have kept a total of nine clean sheets since their 3-0 loss to Arsenal in SEPT ember.
Mourinho feels his former club are unlikely to drop many points between now and May.
“You have to be honest and say that is very difficult,” he told Sky Sports when asked if United could still win the title.
“It’s not just the difference in points, it’s also the Chelsea philosophy of playing.
“They score one goal and they win. They defend a lot. They defend well. They are winning and, in the last 20 minutes, they bring defenders in.
“They don’t care what people say, what people think. They just want to win. And, because of that, I don’t see them losing many points.”