Chelsea midfielder Nemanja Matic says everyone is aware of the importance Diego Costa has to the Premier League champions.
Jose Mourinho hailed the Spain international's man-of-the-match performance in Saturday's 2-0 win over Arsenal after his altercation with defender Gabriel saw the Arsenal man sent off.
Costa was subsequently charged by the Football Association with violent conduct after he caught Laurent Koscielny in the face with his hand during the game - an incident which went unpunished by referee Mike Dean.
And Matic appears all-too aware of the damage which could be caused should the former Atletico Madrid striker face a ban.
"Everyone knows Diego is a great player," the Serbia international told Chelsea's official website.
"You know how many goals he scored last season. He is very important for us. I am happy to play with him."
Matic believes Chelsea have regained some mental strength following back-to-back victories against the Gunners and Maccabi Tel Aviv.
"The game was important to win to get some more confidence," he said.
"We looked better on the pitch. Maybe mentally we are stronger. We had more pressure than normal before the game because we only had four points. We recognised the situation. It was time to win. We played like one on the pitch and we fought for every ball.
"This is just the beginning. In two games we have scored six and not conceded. It’s important for confidence and team spirit, and now we have to continue in this way."
