Arsenal are assessing a groin injury Danny Welbeck suffered against Chelsea.
Striker Welbeck, who missed a good chance in the first half at Stamford Bridge, was taken off during Sunday’s goalless draw.
And boss Arsene Wenger said: “He has a groin problem. I don’t know how severe it is. It looked like it’s not an easy one.”
Wenger was pleased with his team’s display in a fiercely contested derby.
The improved performance came after the Gunners were heavily criticised for their awful showing in the recent defeat at Liverpool.
Speaking at his post-match press conference, Wenger said: “It was a game with total intensity.
“It was a battle all over the pitch and we responded well in the domains we were questioned. I like when the team shows that response.
“We have shown that many times, but you have to accept when you deliver the kind of performance we did against Liverpool that you will be criticised.
“You have to respond on the pitch and we did that. The response for us was even above the result (in terms of importance), and we did that. We did exactly what I expected them to.
“When you are a football player there’s only one thing that matters and that’s the next game and how you respond, and that’s what we did.”