It's difficult to know what will have hurt Jose Mourinho more - a second successive defeat on his old stamping ground, being told to "f*** off" by fans who once worshipped him or being beaten at his own game.
Mourinho's fleeting glances at the immaculately dressed, ultra-intense and ultimately victorious Antonio Conte a few metres to his left on the touchline must have felt like looking at a younger version of himself.
Mourinho was once Chelsea's bright young thing, who won the title at a canter in his first season and didn't look back, before his charm gave way to cynicism and the famous Armani overcoat was replaced by club-issue adidas.
Conte has sailed through his first season in England in a manner reminiscent of Carlo Ancelotti, a man who unlike Conte puts the gentle into gentleman.
Their results have been similar, which bodes well for Chelsea as they seek to win their first double since Ancelotti's historic achievement for the club seven years ago, but the two men's personalities are not.
Conte has more in common with Mourinho than Ancelotti as his touchline theatrics show, but such has been his side's dominance of this domestic season that he has not had to show his dark side.
The 47-year-old's competitive spirit is there for all to see, however, and his desperate desire to end his first season in England at Wembley in May was writ large across Chelsea's team-sheet.
Conte's team selection was a statement of intent all right, and one that was vindicated as it took them through to the semi-finals.
His starting line-up seemed harsh, though, on Cesc Fabregas, who was hugely impressive in starting Chelsea's previous two matches against Swansea City and West Ham United, only to be dropped for the visit of the bigger Manchester United.
And Asmir Begovic must have wished he had signed for Arsenal - whose manager Arsene Wenger picks the club's reserve goalkeeper for Champions League knockout ties - after being dropped to the bench for a mere FA Cup tie.
Conte does not care about upsetting his players' egos, with the irony being that Mourinho would have acted exactly the same.
Throughout all of the United manager's complaints about Chelsea's supposed counter-attacking style, it has not gone unnoticed at Stamford Bridge that he has been lambasting the methods that have underpinned his own managerial career.
All of Conte's decisions paid off, unlike Mourinho's, whose instructions to target Eden Hazard inevitably led to a sending-off.
Nemanja Matic was dominating midfield alongside the irrepressible N'Golo Kante long before Ander Herrera's dismissal.
Chelsea's back three gave no space to Marcus Rashford, whose only sight of goal in the second half ended in a brilliant save from Thibaut Courtois.
Conte was less equanimical about United's overly physical approach, with fourth official Mike Jones frequently getting an ear-bashing on the touchline, but he found no ongoing reason to engage Mourinho.
This will have been particularly painful, as Conte's distant disdain symbolised the fact that for this season at least, United are no longer a threat to Chelsea.
Few men like to be ignored, least of all Mourinho.
THE TIMES, LONDON
