Arsenal manager Arsene Wenger has said that he is unsure of the severity of Theo Walcott's knee injury.

The England international was stretchered off 10 minutes before the end of this evening's 2-0 win over Tottenham Hotspur after coming off worse in a challenge with Danny Rose.

"[Theo] has a knee problem," the Frenchman told ITV Sport. "We don't know if it is a stretched ligament or just a kick, he got two kicks onto his knee.

"Of course if we lose Theo for a longer period, it is a problem."

The 24-year-old held up two fingers in jest towards the Spurs fans - signalling the scoreline - as medics took him down the tunnel.

Wenger said that he has watched the incident back and does not see a problem.

"I have seen the pictures after the game and it does not even look aggressive, he is smiling," he added. "The doctors said to me that the coins had been raining over his head and they had to protect him, maybe that is why he did that.

"You look for every single incident, I can understand that, but it is an action that didn't offend anybody. If [the FA] judge it offensive, what can I say?"

Santi Cazorla and Tomas Rosicky were on target as the Gunners booked their place in the fourth round of the FA Cup.