By Richard Clarke

On Wednesday night, for only the second time in his short Arsenal career, Per Mertesacker will NOT go into a game looking to learn.

At 6ft 6ins tall, the German defender will always be an eye-catching performer. And the unrelenting scrutiny of the Premier League means there is nowhere to hide even if he were that way inclined (and he is not by the way).

Take the first goal against Norwich on Saturday where Mertesacker was muscled off the ball by Steve Morison. Approaching 80 caps for Germany cannot guarantee you protection from a culture shock. It will, however, help you recover more quickly.

But, on Wednesday, the 26-year-old faces a known enemy - Bundesliga champions Borussia Dortmund in a crucial Champions League clash.

Arsène Wenger's side will qualify for the Knockout Stages for the 12th straight season with a victory. That, and a point for Olympiacos, would see them top Group F.

On the eve of the game, the manager was backing his 'biggest' summer signing with words and, more importantly, actions. The Frenchman firmly believes this tall tale will have a happy ending.

"When Per came here he was not completely fit," said Wenger. "But now he is getting stronger and stronger. I felt on Saturday he had not recovered from Germany's game with Holland and looked tired. He has recovered now and will play tomorrow.

"In England, when you're in front of the striker you have not won the battle. In many countries you have. But they fight till the last second here.

"Of course he is under pressure and scrutiny. Yet you don't feel sorry for a situation like that because it's what happens at a big club.

"However he is intelligent and he will adapt quickly. He is very responsible as well. He didn't complain about a possible free-kick [on the Morison goal] because he was pulled down. He just said he should have cleared it earlier."

Mertsacker first showed his mettle to the Arsenal fans in the away game at Dortmund on Matchday One. Robin van Persie snatched the lead for the visitors, they then soaked up waves of pressure before conceding a wonder-strike from Ivan Perisic in the dying seconds.
    
The result set up a confident Group Stage campaign and provided a crucial fillip during an indifferent Premier League start.

Sealing top spot in the return game would give a certain sense of closure to a side whose success is snowballing right now.

Tomas Rosicky (thigh) dropped out just ahead of the final training session on Tuesday but his disappointment allows Abou Diaby to be drafted into the squad for the first time this season.

Like Arsenal, Dortmund have hauled themselves back into contention in their domestic League with an impressive run - P7 W6 D1 L0. They won 1-0 at Bayern Munich on Saturday to move up to second. But they are still playing catch-up in the Champions League. Defeat on Wednesday would leave them relying Marseille on losing their last two.

You could not have predicted that one Matchday One when Mario Gotze et al manipulated the Dortmund attacks so cleverly.

When the German champions were drawn out of Pot 4, it seemed to have changed the face of Group F. Only now are they living up to their billing as top-two candidates.

"Both teams have improved since that first game," said Wenger. "We have grown, they have grown. We have had a similar 'parcours' since the start of the season.

"We had a difficult start, they had a difficult start and we have both picked up since. They were a good team already in Dortmund but we feel strong enough to be at home and finish the job.

"We have come from far. You could see the game at Chelsea has helped the team to improve. Our consistency has helped the team improve. And qualifying from the Champions League group will give us a lift again.

"This game is a cup tie because we have an opportunity in one game to qualify.

"Every player and every member of staff is conscious that it is a big night for us. It's a very important one. It's another big test for our solidity and we will go into the game with that attitude, concentration and desire to win the game. We think we can do it.

"We have a good record at home in the Champions League and we want of course to continue that."

That, by the way, is an understatement. Arsenal are unbeaten in their last 12 Emirates Stadium games in the competition and had won eight in a row before the goalless draw against Marseille last time out.

You have to go back to September 2003 for the last defeat in a Group Stage tie. A 3-0 defeat to Inter Milan when Obafemi Martins overpowered Arsenal's centre-back pairing of Campbell and Toure.

In football years, that is several generations ago.

Right now, you sense the adolescence of Wenger's current team will undergo another significant growth spurt if they can win Group F on Wednesday night.

And Mertesacker's local knowledge will help.
 
Team news

Arsenal - Sagna (ankle), Gibbs (stomach), Rosicky (thigh), Wilshere (ankle)
Dortmund - Kagawa (doubt - toothache)

Referee: Frank de Bleeckere (Belgium)

  • Tomas Rosicky will face a Uefa suspension if he is booked.
  • Arsenal have currently scored 247 European Cup/Champions Legaue goals, conceding 149.
  • Arsenal have won their last five European home ties against German opposition.
  • Tomas Rosicky scored 19 goals in 149 Bundesliga games between 2000 and 2006.
GROUP F
Pos. Team P W D L F A Pts
1. Arsenal 4 2 2 0 4 2 8
2. Marseille 4 2 1 1
4 1 7
3. Borussia Dortmund 4 1 1 1 3 7
4
4. Olympiacos
4 1 0 3 4 5 3
Copyright 2014 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source 23 Nov 2011