Arsenal midfielder Mikel Arteta has admitted that his side weren't ruthless enough in their defeat to Manchester United at the Emirates Stadium.

The Gunners spurned several good chances in the first half as they dominated the Red Devils, but in the second they fell behind to an own goal from Kieran Gibbs and lost the game late on when Wayne Rooney scored on the break, despite a late strike from Olivier Giroud.

Arteta told Sky Sports News: "After they took the lead we had to take more risks to try to get back into the game and United have the players up front to cause you problems at any time.

"But I feel so sorry for the lads and for our supporters because they were terrific and I don't think we deserved this result.

"It's [a lack of] ruthlessness, for sure. When you are in the box and you can't manage to score in that many situations, you can't expect to win."

Arsenal face Borussia Dortmund in their Champions League clash on Wednesday.