Koscielny stepped in to cover for the absence of Thomas Vermaelen.
Wenger said: "He had 'flu yesterday, and we left him at home. But Laurent Koscielny had a great game and stepped in very well. We have three classy centre backs, and it is a very difficult choice. Koscielny, Mertesacker and Vermaelen - no matter who is left out can feel it is not right. But I will rotate them and take into consideration the strikers we will face."