Tottenham moved back to the top of the Premier League after a 0-0 draw against London rivals Chelsea at Stamford Bridge on Sunday.
Spurs climbed above previous leaders Liverpool on goal difference after a sterile London derby at Stamford Bridge.
The North London club are unbeaten in nine league games and Mourinho seemed happy to frustrate his former club as they adopted a cautious approach with little attacking ambition.
Chelsea have not lost in their last 11 games in all competitions and sit in third place, two points behind Tottenham and Liverpool, who drew 1-1 at Brighton on Saturday.
Fourth-placed Leicester would go second if they beat Fulham on Monday.
Timo Werner thought he had put Chelsea ahead early in the first half with a superb finish, only for an offside flag to thwart the Germany striker.
Chelsea’s Mason Mount forced a good save from Hugo Lloris in the second half, while substitute Olivier Giroud should have done better than shoot straight at the Tottenham keeper in stoppage time.