Manchester United boss Jose Mourinho told Chelsea supporters "Judas is number one" after Antonio Conte guided the Blues into the FA Cup semi-finals.
N'Golo Kante's strike settled a bad-tempered contest 1-0 to set up a FA Cup semi-final with Tottenham for Conte's Premier League leaders, who could yet claim a double in the Italian's first season in charge.
Ander Herrera was sent off for two bookable offences and United players surrounded referee Michael Oliver, while Marcos Rojo appeared to tread on Eden Hazard. The Football Association may scrutinise those incidents and retrospective action could follow.
Mourinho, Chelsea's most successful manager, pointed to himself, then the pitch and signalled with three fingers - for the number of Premier League titles he won in two spells - after being subjected to abuse from a section of fans behind the visiting dugout.
One section of supporters chanted "F*** off Mourinho", "It's all your fault" - a reference to Chelsea's implosion last season - "You're not special any more" and "Judas".
"They can call me what they want," Mourinho told the post-match media conference.
"Until the moment they have a manager that wins four Premier Leagues for them, I'm the number one. Judas is number one."
Mourinho was sacked by Chelsea for a second time in December 2015, seven months after his third title success.
He again bemoaned the fixture schedule which saw the quarter-final tie take place between legs of United's Europa League last-16 tie with FC Rostov.
But he insisted Chelsea's absence from European football was not his responsibility as when he was axed, with the Blues perilously close to the relegation zone, they were still in the Champions League under interim boss Guus Hiddink.
He added: "It's not my fault. It's the fault of the ones that stayed here and didn't win the Champions League."