Mikel Arteta slammed the Arsenal performance as "sloppy" as they lost 2-0 to Borussia Dortmund on Tuesday evening.

The Gunners kicked off their Champions League campaign with a disappointing reverse away to the Bundesliga giants, and Arteta accepted that the side were second best throughout.

"We faced a top side, one of the best in Europe, we knew that from the start," Arteta told Sky Sports News.

"We put them under pressure, but it was sloppy from us to concede a goal, just with 20 seconds to go in the first half. It was our own throw-in on the other side of the pitch. After we go 1-0 down, it is difficult. They are very good on the break. We didn't perform well enough tonight.

"They have a lot of pace and have pressure up front. We gave the ball away too many times in difficult positions. They took the game where they wanted to take it. We had three or four clear chances, but I think they were the better side tonight."

Elsewhere in the group, Galatasaray drew 1-1 with Anderlecht.