Chelsea goalkeeper Kepa Arrizabalaga has appeared to openly defy his manager Maurizio Sarri during the League Cup final defeat to Manchester City, refusing to be substituted near the end of extra time at Wembley.
It was one of the strangest incidents ever seen in a Wembley final and the repercussions for both could be serious.
Here is some of the reaction to the bizarre sequence of events involving Sarri and the world's most expensive keeper.
Former Chelsea forward Chris Sutton, talking to the BBC:
"Kepa should never play for Chelsea again. That should be his last performance in a Chelsea shirt. He's a disgrace. I've never seen anything like it.
"If I was Sarri I would walk. You cannot be undermined. Why weren't the players dragging Kepa off anyway?
"Kepa should be sacked, not Sarri."
Former Chelsea player Craig Burley on Twitter:
"If the Kepa incident was just one big misunderstanding, this explains why Sarri was still trying to kill him just before the pens."
Former England midfielder Jermaine Jenas, now BBC pundit:
"For one of the players to really go against Sarri on such a public stage doesn't sit well with me.
"This is a huge blemish. It all boils down to what is going on between Sarri and his players. That does not happen - there's a lack of respect some way along the line."
Man City club captain Vincent Kompany on Sky Sports:
"I know how good Willy Caballero is on penalties. Last time we won it, he won it for us, so I didn't want him to come on! It didn't happen in the end."
Former Chelsea skipper John Terry, talking to Sky Sports:
"It will be interesting to see if Kepa plays the next game. If I was in the dressing room I would expect the manager to come in and deal with it straight away."
Former England captain and now BBC presenter Gary Lineker on Twitter:
"Wow! This is bonkers. Not sure I've ever seen a player refuse to be subbed. Extraordinary."
Former England midfielder Jamie Redknapp on Sky:
"Once your number comes up, you are off the field no matter how much it hurts. You've got to have respect for your mate that's coming in for you.
"It not like he's (Sarri) decided to take him off for no reason. He's taking him off because he's had cramp twice on the pitch.
"I feel so sorry for Sarri. In that situation, that's a killer. It's really hard for him."