Antonio Conte was sent off as Chelsea claimed a fifth Premier League win in six games with a 1-0 defeat of Swansea.
Head coach Conte was dismissed from the touchline for the first time in his Chelsea career by referee Neil Swarbrick moments before half-time after furiously protesting the award of a Swansea goal kick.
Willian's cross diverted off Alfie Mawson, but instead of awarding a corner, Swansea were given a goal kick.
Conte remonstrated at fourth official Lee Mason, who called over Swarbrick.
He was sent to the stands. He initially clambered behind the dugout, but then had to move due to the proximity of his new seat to his coaching staff.
The Blues boss watched the second half from the dressing room as Chelsea owner Roman Abramovich saw Antonio Rudiger's goal prove decisive.
The Blues' only dropped points in their last six league games came at Liverpool last Saturday, while Swansea suffered a 10th loss of the season.
After coming off the substitutes' bench to net the equaliser at Anfield, Willian started for the first time since the October 14 loss at Crystal Palace as Conte rotated his options.
Cesar Azpilicueta did not start a Premier League game for the first time under Conte. A run of 74 league starts, since December 2015, ended as Eden Hazard also dropped to the bench for Chelsea.
It was like a training drill of attack versus defence which featured two penalty appeals for the Blues.
The first came when Alvaro Morata, who with eight league goals this season has one more than Swansea as a team, and Mike van der Hoorn grappled in the area. Marcos Alonso next felt he was tripped by Renato Sanches.
Lukasz Fabianski saved from Morata, Davide Zappacosta and Pedro, twice, and Willian curled an in-swinging free-kick wide.
Fabianski saved a Morata header and next tipped over after the striker acrobatically hooked a Cesc Fabregas cross towards goal.
Alonso headed wide from a Fabregas corner before the denial of another set-piece angered Conte. Sanches, on loan at Swansea from Bayern Munich, was replaced at half-time after an ineffective display which had seen him pass to the opposition and out of play.
Swansea improved in the second half, but still Chelsea attacked time and again.
Pedro scooped over before the Blues netted. N'Golo Kante's shot deflected off Wilfried Bony's head into the path of Rudiger, who showed a striker's instinct to head in for his first league goal.
Alonso had a shot blocked, Morata clipped an effort over and Willian's shot was parried by Fabianski as Chelsea spurned the chance to add a second.
Swansea had few forays forward, but almost stole a point only for substitute Wayne Routledge to cross too far in front of Bony. Swansea now are without a goal in four games.