Antonio Conte and Jose Mourinho had to be separated as N'Golo Kante's strike sent Chelsea into the FA Cup semi-finals with a 1-0 win over Manchester United at Stamford Bridge.
Fourth official Mike Jones had to intervene as Conte and Mourinho had a frank touchline exchange during a feisty contest in which United had Ander Herrera sent off for two bookable offences after 35 minutes.
Kante's second Chelsea goal six minutes into the second half secured a quarter-final win for the Premier League leaders, who won for a club record 13th successive home game.
Hopes of a double in Conte's first season in charge remain alive.
Both Kante's Chelsea goals have come against United, who have not beaten the Blues in 12 attempts, since October 2012.
Mourinho, whose side won the EFL Cup last month, had never lost a FA Cup quarter-final. He has now.
David de Gea made fine saves in quick succession to deny Eden Hazard and Gary Cahill and a smash and grab raid for United appeared possible.
But Herrera was dismissed for two fouls on Eden Hazard following what looked like an edict to target the Belgium playmaker.
United players surrounded referee Michael Oliver to complain, but captain Chris Smalling had been warned seconds earlier about repeated fouls on Hazard after one by Phil Jones.
The visitors attempted to intimidate and impose themselves, but Chelsea - and Kante and Hazard in particular - were indomitable.
Mourinho is Chelsea's most successful manager and Conte spoke of his desire to emulate the self-proclaimed Special One last Friday.
The Italian also asked for Mourinho's history to be respected, but the United boss had to remind home supporters behind the visiting dugout of his three Premier League titles.
The apathy which greeted Mourinho in defeat last October - when his return was overshadowed by the 20th anniversary of the death of Matthew Harding - had turned to animosity.
The last time Mourinho was an FA Cup manager on this ground, Chelsea conceded a two-goal lead to lose to League One Bradford.
And he suffered his biggest defeat in English football when Chelsea won 4-0 in the Premier League last October.
Mourinho rebuked Conte on that occasion after the Italian had implored the crowd to cheer with Chelsea coasting.
Conte vowed not to tone down his exuberance in his technical area and he refused to be cowed as Mourinho's men made their presence felt.
Marcos Rojo's challenge from behind on Diego Costa set the tone as United repeatedly resorted to the cynical, while Jones was deployed as Hazard's shadow.
In Marcus Rashford, who declared himself fit following illness to ensure United could field a recognised striker, the visitors had a potent weapon.
Rashford's pace and energy made Chelsea's defence nervous and his persistence resulted in a chance for Henrikh Mkhitaryan to fire wide.
Hazard, sparkling this term as he did under Mourinho in their title-winning campaign together, attempted to make the most of the few occasions when Jones' attention was diverted.
He turned Smalling, skipped by Rojo and his shot through Matteo Darmian was deflected, only for De Gea to turn the ball around the post.
De Gea made an even better save from the resulting corner, as Cahill held off Rojo and shot, only for the goalkeeper to intervene.
Herrera blocked Hazard as he looked for a one-two with Costa and then the Belgian sliced wide after Jones committed to a challenge on Nemanja Matic.
Jones felled Hazard, United were warned by Oliver and moments later Herrera's daft challenge saw him booked for a second time.
There was an eruption of fury and a wry smile from Mourinho, who immediately withdrew Mkhitaryan and sent on Fellaini.
Mourinho and Conte made their feelings towards each other clear, but Chelsea had the numerical advantage and began to exploit the space.
Paul Pogba and Kante had been within touching distance of each other throughout the first half.
But a split-second lapse from Pogba was punished by his fellow France international as Kante drilled the ball into the bottom corner from the edge of the area.
Thibaut Courtois saved from Rashford as United were denied an equaliser, while Chelsea three times came close to a second.
Costa spurned a free header from a corner before Willian curled over after Kante brilliantly deceived Fellaini on the edge of the area.
And De Gea denied substitute Cesc Fabregas in stoppage time as the Blues prevailed.