كتب : وكالات
"It was a blatant penalty, under the eyes of the referee," the Frenchman told BBC.
Alexander Hleb was fouled in the area by Dirk Kuyt but the Dutch referee was well placed and kept his whistle in his hand.
"I feel we were not rewarded for what we produced - and we had the chances to win it.
"We were a bit unlucky with a big decision of the referee on the penalty. It's difficult to take, but we have to swallow it."
The Gunners will face Liverpool on Saturday in the Premier League and Tuesday in the Champions League at Anfield.
"It is now a little bit of a survival battle. The one who is still good after three games is the one who is the better team."