Arsenal boss Arsene Wenger admits his side lacked their usual sharpness as they went down 1-0 to Sunderland on Saturday.

The Gunners looked toothless up forward without Robin van Persie and Nicklas Bendtner indicating Wenger may need to dip into club funds and buy a striker in January, especially if they are to bridge the gap on league leaders and next league opponents Chelsea.

"Going forward we lacked sharpness, we lacked the desire to go behind defenders. We've chosen the easy part of the game and not exposed them with our pace in behind," the Frenchman said.

"If you want to score goals you have to go behind the defenders. We choked a little bit and chose the easy part of the game."

Wenger said it was a major disappointment to give up the points the way they did and slip behind the leading duo of Chelsea and Manchester United.

"Mentally it's a blow. It's a big disappointment because we know it was a very important game that we couldn't afford to lose and we perhaps under-estimated how difficult it would be for us here," he added.

"Give Sunderland credit, they defended with a lot of heart and great desire and they fought for every ball. They played it like it was a cup tie.

"We had more of the ball so they tried to stop us from playing. Sometimes they were on the fringe of the rules but that's part of the game."