Willian struck an 89th-minute winner as Chelsea beat Everton 1-0 but the Premier League leaders could face disciplinary action once more after Branislav Ivanovic appeared to headbutt James McCarthy.
The flashpoint occurred after Nemanja Matic thought he had scored four minutes from time, only for the deflected strike to be ruled out for offside against Ivanovic, who had blocked the view of Everton goalkeeper Tim Howard.
Tempers flared when Gareth Barry then tripped Willian, earning a second yellow card, and Ivanovic motioned his head towards McCarthy in the resulting fracas.
The Everton substitute was booked for his part in the melee, but Ivanovic avoided censure from referee Jonathan Moss and could face retrospective action from the Football Association.
There was still time for Willian to net after Howard was unconvincing in clearing a cross as Chelsea remained seven points clear of Manchester City.
It could have gone either way until a frantic final four minutes.
The suspended Diego Costa scored twice in August’s 6-3 win at Goodison Park and would have relished the chances created by Chelsea, but the Blues struggled to test fit-again goalkeeper Howard.
Instead it was Petr Cech who had to show his enduring quality after being selected ahead of Thibaut Courtois.
He twice saved from Romelu Lukaku, the second time when the former Chelsea striker was four yards out, and Mourinho made a point of going to Cech at full-time.
Mourinho, who was last month fined B£25,000 for saying there was a “clear campaign” against Chelsea, continues to imply his side are unfairly treated and two decisions went in favour of Everton in the opening quarter of the contest.
Chelsea might have had a fourth-minute penalty when the ball hit Steven Naismith’s arm and Everton had another reprieve when Barry fouled Juan Cuadrado and Eden Hazard in quick succession, but was booked only for the first offence.
The FA Cup loss to Bradford gives Chelsea a rare weekend off and Costa will be available for next Tuesday’s Champions League last-16 clash at Paris St Germain following his disputed three-match suspension, before returning to aid the title tilt.