Chelsea defender Kurt Zouma has admitted that team-mate Diego Costa "likes to cheat a lot".
The Chelsea striker infuriated Arsenal with his antics during the 2-0 win on Saturday that saw Gunners defender Gabriel sent off after clashing with the Spain international.
Zouma admitted Costa "cheats" to put his opponents off but insists Chelsea are proud to have him in the team.
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He told beIN SPORTS: "Everyone knows Diego and this guy likes to cheat a lot and put the opponents out of his game, and that happened in the game. He’s a real nice guy in the life and we are very proud to have him."
Costa could yet face action from the Football Association regarding his actions against the Gunners.
Jose Mourinho was seething when Costa was retrospectively sanctioned in February for treading on Liverpool’s Emre Can, part of what the Chelsea boss perceived as a "campaign" against his side which included a Sky Sports montage entitled ‘Costa’s Crimes’.
But Arsenal boss Arsene Wenger said he hoped referee Mike Dean would look again at Costa’s actions before filing his match report on Monday.
The match officials should have been aware of Costa’s reputation during his first 14 months in the Barclays Premier League, says Wenger, but statistics show the striker did not commit a foul in the match.
Gabriel became involved after Costa grappled with Koscielny, pushing the defender in the face with his hands before catching him with a flailing arm.
Zouma scored the first goal against Arsenal and was a tower of strength in defence – and said he is still learning from skipper John Terry, who was on the bench at Stamford Bridge on Saturday.
He added: "John Terry is an example for me and a really good tutor for me and he will be there for next game – he’s our leader. Now we have to just recover our defensive organisation like we had last year – it does matter how plays we just have to keep going and keep clean sheets.
"It was an amazing feeling for me – when you play big derbies you are always excited and for me it was an amazing game because I scored a goal and we won again. So we are very happy – with the goal, with the win and with the clean sheet as well."
The 20-year-old French defender said Chelsea could now kick on and put their poor start to the Premier League behind them,
Zouma said: "We don’t have pressure in the dressing room, we know who we are. We had some bad results since the beginning of the season but we showed who we are and we know what we can do and we just have to keep going and there is still a long way to go."