Arsenal boss Arsene Wenger has admitted that he is "a bit worried" he could lose defensive midfielder Francis Coquelin for a prolonged period of time.

The Frenchman picked up an injury in the 3-0 win over Chelsea on Saturday to provide the only blemish on an otherwise perfect occasion for Wenger to mark 20 years in charge of the Gunners.

Coquelin attempted to play on but was forced to admit defeat when limping off with 36 minutes on the clock, and his manager now fears a repeat of last season when the 25-year-old spent two months on the sidelines with ligament damage.

"He has a knee injury at the same place he had last year at West Brom," Wenger is quoted as saying by The Independent. "That's the negative of the day.

"We don't know if the damage is as big at the moment, we have to wait. But he left the stadium in a brace and I'm a bit worried for that."

Arsenal, who climbed up to third place thanks to their first win over Chelsea in five years, are anticipating an update on Coquelin's injury problem at some point on Monday.