Arsene Wenger took their setback against Borussia Dortmund hard, as they were able to take control of the game before the German side was able to score their second and winning goal at the 82nd minute mark in their UEFA Champions League showdown.

"It's difficult to take because we were maybe not at our most fluent tonight going forward, but at that moment [of the second Dortmund goal] we were on top," Wenger told uefa.com.

Used to getting wins in their recent games, the Gunners forgot what a point can mean, especially in a group as tight as theirs.

"We lost the game because we wanted to win it so much that we forgot that if you cannot win it, don't lose it. That's what is most annoying because we put a lot of effort in," he added.

Wenger admitted that his squad was not as sharp as they were in their previous games.

"We started hesitantly and gave them confidence. Our fluent football was not quick enough," he noted.

"We went 1-0 down and when you don't start well it is difficult to get back into the game. But we did well and in the second half we were on top. We just forgot to be cautious."

Lack of concentration coupled with a determined opposition in Dortmund ultimately cost the Gunners, at least, one point.

"We were not cautious enough and we paid for it. We put ourselves on the back foot for the first goal, and we were naive for the second," he said.

"It was a game of high intensity but very few chances. Dortmund were well organised to stop us playing."

The French manager noted that fatigue may have set in on his players, but stresses the importance of a defeat in moulding the team holistically.

"Disappointment is part of how a team grows. Some players are a bit jaded," he revealed.

"The group is tight and difficult for us, but possible. We need a result away from home."