However, Costa was adamant that there was no foul play after a defeat which effectively ended Chelsea’s season.
“Diego spoke to club officials after the game and expressed regret over his reaction to the challenge from Gareth Barry that led to his red card,” said a Chelsea statement.
“But Diego was also very clear that he did not bite him at any point during that altercation.”
To add to the late drama at Goodison Park, Barry was also booked in the flashpoint and received a second yellow card of his own in the dying minutes after fouling Cesc Fabregas.
Chelsea interim manager Guus Hiddink refused to condemn Costa after the first sending off of his Blues career.
The Dutchman even managed to laugh off the incident, with reference to the Hollywood movie “Anger Management”.
“There are movies about that,” said Hiddink when asked if he will advise his player to seek counselling.
“I have seen that film. Maybe we will go and watch it together. I try to be fair in my judgement and I haven’t see it (the incident) so far. But without wanting to give a judgement, he was chased a bit in the game as well.
“They went after him, they know it. It’s within the rules but, as a referee, you must protect the situation a little bit. I’m not saying ‘PROTECT’ with capitals, but knowing and feeling the atmosphere, the little provocations.”
Any FA punishment will depend on referee Oliver’s report although Hiddink repeated his often-stated position of insisting he does not want Costa to alter his combative style.
“I like him,” said Hiddink, who praised Costa for wanting to play despite suffering injury in the midweek Champions League loss to PSG.
“I still like he is going towards the edge but you also have to take into consideration he desperately wanted to play today. It would have been better for him to be rested but this was not the type of game where you rest players.”
Meanwhile, Romelu Lukaku insisted he had nothing to prove to his old club after his two spectacular late goals earned Everton the victory against his former employers.
The 22-year-old Belgian international had his path to first team football blocked at Stamford Bridge, moving to Goodison Park on a season-long loan before signing in a £28 million (36.1 million euros) permanent deal in the summer of 2014.
Now, with 25 goals for Everton this season, that investment by Roberto Martinez looks a sound one, although the player himself insisted that he was not motivated by any sense of revenge in facing Chelsea.
“I don’t think I have anything to prove,” said Lukaku. “Obviously there is a bit of emotion. I went there as an 18-year-old kid, that’s where I learned my trade to be a professional footballer.
“But I moved on, like they did. I wish them the best for the future but do my best for my team.
“I think the first goal is my best of the season but it’s just another goal.
“I am just happy for the team, we really wanted to win today. If you want to win cups, you have to win against the big teams and that’s what we did today.
“It feels great, I’m just happy for the team. It’s something we wanted and now we’re almost there, 90 minutes to go. We delivered a good performance today after the loss against West Ham.”