Arsenal manager Arsene Wenger has admitted that he was "surprised" by how quickly Ludogorets Razgrad started their Champions League clash in Sofia this evening.

The Gunners found themselves two goals down inside 15 minutes against the Bulgarian champions courtesy of quickfire goals from Jonathan Cafu and Claudiu Keseru.

Arsenal did recover to win the match 3-2 through goals from Granit Xhaka, Olivier Giroud and a late strike from Mesut Ozil, but Wenger acknowledged that his side found it tougher than their 6-0 win in the reverse fixture at the Emirates.

"We needed to keep our composure. I believe we were surprised by the speed of their start but after that we came back to 2-2 which was positive," he told reporters.

"We were less fluent in the second half but we eventually got a goal close to the end. Ludogorets maintained their intensity for 90 minutes so it was more difficult than at the Emirates where they dropped off."

Arsenal's victory means that they are now guaranteed a place in the knockout rounds of the Champions League for the 17th consecutive season.