Let's get one thing clear -- players are supposed to listen to their coach, follow instructions and do what's in the best interest of their team. Now, there are always mistakes, but what happened to Chelsea in the EFL Cup final against Manchester City on Sunday could spell the end to the Maurizio Sarri era. He decided to sub off his goalkeeper, Kepa, late in extra time with the young Spanish player refusing to come off, undermining his coach and the club in the process. Here's everything you need to know about the bizarre incident in Chelsea's loss.

What happened?

Late in the final, with the score 0-0, Kepa complained about an injury. He even raised his arm and was looked at by the medical staff. So Sarri decided to take him off and use backup Willy Caballero in the penalty kick shootout. But Kepa claimed that he was fine and refused to come off the field, which infuriated Sarri and his assistants. Take a look:

Did it have a big impact on the result?

Caballero, of course, used to play for Manchester City. He's a quality penalty kick stopper, he knows the other players and their tendencies well, and yet he didn't get his chance. City went on to beat Chelsea in the shootout, 4-3, with Kepa saving one and blowing another save he looked to surely have. 

As to whether it had an impact, it's is hard to tell. We can't really attribute the failed save on Sergio Aguero to him being injured, and there is no guarantee that if Caballero were to have played that Chelsea would have won. 

What did Sarri say?

In his post-match press conference, Sarri said it was a "big misunderstanding," adding that Kepa went about it the wrong way. The incident -- "misunderstanding" or not -- clearly ticked Sarri off given his reaction on the sideline. He called for a sub, and his player refused to come off. There's no misunderstanding. Sarri made the decision to swap him, Kepa tried to claim that he was fine and somehow managed to stay on. 

What did Kepa say?

He took to Twitter to say he respects the coach and his authority and that he didn't intend to disobey him, simply to express that he felt fit enough to continue. He went on to say that he doesn't agree with how the end of the match is being portrayed.

So what's next?

More than the result, this speaks to the current situation at the club. Bad results, a player not listening to the coach and losing an important final doesn't speak well to how things are going. 

Kepa has some explaining to do, and Sarri has to figure out why the goalkeeper went against his orders, despite trying to save face.

You can see City and Chelsea in the Premier League on fuboTV (Try for free). 

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