Arsenal vs Borussia Dortmund: Arsene Wenger maintains belief that Gunners can top group and eyes improvement before knockout stages

Wenger says his side need to up their performance levels in order to compete with the best teams in Europe

Arsenal manager Arsene Wenger has challenged his team to turn themselves into Champions League contenders by the time the knockout stages come around next year.

The Gunners put their recent troubles behind them to beat Borussia Dortmund 2-0 at the Emirates Stadium on Wednesday night and qualify for the last 16 with a match to spare.

Should the results go their way in the final set of fixtures in Group D - leaders Dortmund, who had won all four of their previous European ties, suffer an unexpected home defeat to Anderlecht and Arsenal win away at bottom club Galatasaray - then Wenger's side could yet progress as top seeds.

Having seen Arsenal paired with the likes of Barcelona, AC Milan and Bayern Munich in recent seasons, Wenger feels no matter which team they will be drawn against, the Gunners must go into the ties in top form.

"If you look at the last five or six years, we got the teams we didn't want. From now until February, we need to improve as a team, get encouragement from the Dortmund game and then hope we have nearly all our players back in the next round," said Wenger.

"You see who is qualified around Europe and there are many teams who are at the top, top level. There are three or four teams you don't want to play."

Wenger, whose team blew a 3-0 lead at home to Anderlecht on matchday four, added: "I will try to win the last game and you never know.

"If Anderlecht win in Dortmund and we don't win in Galatasaray you will say we were stupid.

"It is unlikely, let's say it is 90 per cent that we will finish second and Dortmund will finish first."

The Gunners have endured their worst start to a domestic campaign for 30 years and are eighth in the Barclays Premier League following Saturday's 2-1 home defeat to Manchester United.

However, Wenger's men produced the perfect response on Wednesday night as Yaya Sanogo scored inside two minutes with Alexis Sanchez clipping home a sublime effort at the start of the second half to kill off the challenge of the Bundesliga strugglers.

"What is important is that we are united," Wenger said.

"This team has a top-quality attitude and we have shown after the disappointment on Saturday that we were united in the game, determined, committed and after that people take what they like or don't like - we have to accept that.

"What is important is what we do inside the club."

Wenger admits the current injury situation "is a problem".

Captain Mikel Arteta limped off with a calf problem, along with goalscorer Sanogo, who has picked up a hamstring injury.

Midfielder Jack Wilshere is set to see a specialist on Thursday for an update on his damaged ankle which may require surgery.

England forward Danny Welbeck was missing with a knee problem, while fit-again Olivier Giroud had not been registered for the Champions League squad and so will be in line to return at West Brom on Saturday.

While Arsenal can now look to build some momentum, Borussia Dortmund return to Germany with more questions on the direction of Jurgen Klopp's side, who have slumped into the bottom three of the Bundesliga.

Klopp said: "We have to work. Work always works in life.

"We will get it back. We don't need perfect football, we just need good results and we can play better."

PA