Thierry Henry and Jamie Redknapp have both criticised Chelsea forward Diego Costa for his performance against Liverpool.
Costa appeared to stamp on both Emre Can and Martin Skrtel in separate incidents, also clashing with Steven Gerrard.
Chelsea won the game 1-0, 2-1 on aggregate, thanks to a Branislav Ivanovic goal in extra time.
Former Arsenal striker Thierry Henry told SkySports he felt Costa's fiery nature was a strong point of his game, but on this occasion he deserved to be sent off.
He said: "I love the aggressiveness but I think he went a bit too far there. I think it was a red. (On the Emre Can incident) The referee didn't see it, the linesman didn't see it, fourth offical didn't see it, but I think it was a red."
Fellow analyst Jamie Redknapp was more forthright, but also said Liverpool should have also had red cards handed to their players for separate offences by referee Michael Oliver.
He said on Costa: "There's a fine line between an aggressive action and a violent action, but he's crossed it."
There remains a possibility the FA take retrospective action against Costa, because neither incidents went punished by the officials.
Costa's performance was great viewing for the neutral, but just like Luis Suarez used to at Liverpool, he has a habit of getting under the skin of opposing players and fans, and appears to relish playing the villain.
Had he badly injured either of his opponents with his challenges, which was very possible, it would not be so easy to dismiss his actions as simply being part of his game.