The Spanish striker has been declared fit to play after recovering from a shin injury and Wenger is wary that the Brazil-born Spain international will be up to his old tricks again at the Emirates Stadium this weekend.
Costa was involved in several altercations when Arsenal lost 2-0 to Chelsea at Stamford Bridge back in September - and Wenger wants his players to be more wary of the 27-year-old this time around.
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“We have to be prepared for a battle because Costa gives you a fight,” the veteran French coach was quoted as saying by the Daily Mail. “After that, it’s down to the referee.
“It’s a difficult subject. We have to focus on our performance and forget a little bit about (Costa).”
Costa was the pantomime villain in reverse fixture
In the reverse fixture, Costa somehow avoided punishment after lashing out at Laurent Koscielny before he stood on the foot of Gabriel, prompting the Brazilian defender to foolishly kick out and earn himself an early bath.
The Football Association later rescinded Gabriel’s red card and handed Costa a three-match ban instead - but nothing could be done about the three points Arsenal lost on the day.
Arsenal must keep all 11 men on the pitch
The experienced Wenger will be acutely aware that the best way to win this weekend is to keep all eleven men on the pitch.
Not reacting when Costa inevitably attempts to antagonise his opponents will be crucial for the likes of Koscielny and Per Mertesacker on Sunday.
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