Arsene Wenger believes Arsenal are progressing and will continue on upward curve

Arsene Wenger: Happy with Arsenal's form but hopeful of further improvement

Wenger's men have enjoyed a superb start to the Premier League season, sitting top of the table, and continued their excellent form with a 4-1 win over Norwich on Saturday.

They head into a rematch with the German side, who they took four points from in 2011-12, having won their first two Champions League group matches as well, and Wenger can only see further improvement coming from his side in the future.

"I believe we are much better. Our young players have gained experience and maturity," Wenger said.

"The consistency of our results since January shows that. We are capable to be consistent and that is always a sign of quality, especially in the Premier League.

"The feelgood factor is down to what I have said many times; the quality of the spirit of the team, the solidarity of the players and the desire to do well. We are a team that looks to be successful, which needs a special hunger, and I think we have that.

"We have room for improvement and being in a position we are in at the moment, knowing we have that is of course a good thing.

"In life you can always improve and that search for improvement is what can make a top-level sportsman or top-level team. Collectively, the way we win the ball back and the use of the ball offensively we have room for improvement and for more consistency, and that's what you want from your players.

"What is important is that we go into the game and focus on our quality and our performance. That is more important than focusing on Dortmund. If we play at our best we will be difficult handle for everybody."

Wenger has confirmed Mathieu Flamini will miss the European clash with Dortmund.

Flamini suffered a concussion in Saturday's 4-1 Premier League win over Norwich, and although the Group F clash is vital in their potential progress to the last 16, he will not be risked.

Wenger said: "Flamini is doing well, has practiced normally, but we will not play him tomorrow.

"There is a five-days (concussion) rule that we will respect, not to take any chance. It was a concussion and the doctor advised us not to play him. He will be okay for the weekend.

"I'll leave myself 24 hours until tomorrow afternoon to decide the team."

Wenger had earlier revealed that Theo Walcott had suffered an injury setback in training and is expected to spend another two weeks on the sidelines.

The England international has been struggling to regain full fitness following groin and stomach surgery.

Wenger said: "He had a setback on Thursday. He had to stop, to jog again.

"I don't think we will see him against Dortmund nor Crystal Palace nor Chelsea.

"He is at least two weeks away now."