With Arsenal losing heavily at Liverpool, and Manchester City only collecting a point against Norwich City, Mourinho's side took full advantage to climb to the summit.
And the Portuguese admitted he was not expecting to move above Arsenal and City, repeating his mantra that his team should not be considered favourites to win the title.
"Big results are always surprising, of course they can happen but always surprising, you never expect such a big result (as Liverpool's 5-1 win)," Mourinho said. "Everybody knows Anfield is not an easy place to play, it can happen to anyone.
"The other matches are matches where you can show that you are better or you can have a difficult situation.
"Norwich is not easy, we beat them there in the last minutes. When it happens to City it is more surprising (because) their attacking power is amazing.
"I think we are playing well, the first half was not the best example of that, but we are playing well.
"People individually are in a good moment, the team is getting good results and we are top of the league which is something we can't hide.
"This team are just starting and I don’t want to compare (them to his previous side), (but) potentially this team is good and hopefully we will have a good decade.
"They are young guys with lots of years to play."
Mourinho was particularly impressed with hat-trick hero Eden Hazard, and praised the Belgian for consistently delivering for Chelsea this season.
"I think his performance today was not different to other performances he has," he added. "The only difference was he scored a hat-trick for the first time.
"He's playing really well, (he has had a) big evolution, (and has shown) consistency, ambition - (he is) fantastic."
