Chelsea's title hopes suffered a blow when the Premier League leaders finished with nine men in a 1-0 defeat at Aston Villa.
Visiting Chelsea thought it took the lead in the 41st minute when midfielder Nemanja Matic poked home from close range following a corner, however he was alleged to have handled the ball first.
The second half sprung to life after Chelsea midfielder Willian was sent off in the 68th for two bookable offences.
Referee Chris Foy's decision handed Villa the incentive, and they eventually capitalised through Fabian Delph.
The midfielder converted in the 82nd minute with a masterful flick, denting Chelsea's title surge.
Chelsea then found themselves down to nine men when midfielder Ramires was then shown a straight red in second-half stoppage time for a wild lunge at Karim El Ahmadi.
That sparked animated scenes on the touchline, which eventually led to Mourinho being dismissed for his remonstrations.
Kompany sees red
Manchester City bounced back from their FA Cup and Champions League exits to beat Hull City 2-0 with 10 men to keep their Premier League title hopes alive.
City had captain Vincent Kompany sent off after 10 minutes for hauling down striker Nikica Jelavic on the edge of his own box, but they took the lead two minutes later through David Silva before Edin Dzeko added the second in the 90th minute.
Silva scored with a superbly executed curling shot in the 12th minute after a delicate pass from Yaya Toure and although Hull battled gamely, City made light of their one-man disadvantage and stretched their unbeaten away run in the league to eight games.
Dzeko wrapped up the points from point blank range after a pass from Silva.
Chelsea stay top with 66 points from 30 games, above second-placed City who have 60 points but with three games in hand.
Liverpool and Arsenal, who play Manchester United and Tottenham Hotspur respectively on Sunday, are tied in third place with 59 points.
Everton win thriller
Everton scored in the third minute of injury time to beat Cardiff 2-1 and provisionally climb above Manchester United to sixth place, two points behind Tottenham.
The bottom five teams are separated by just five points after last-place Fulham beat Newcastle 1-0 at Craven Cottage.
West Brom moved away from the relegation zone by defeating Swansea 2-1 away and Southampton secured a 4-2 win over relegation-threatened Norwich.
Crystal Palace held Sunderland to a 0-0 draw in another game between two sides fighting to stave off relegation.