"It is vital to keep a clean sheet," the Frenchman said on Monday.

"Nil-nil is not a disaster at home, but of course we will try to score goals."

The Gunners exited the FA Cup at the weekend with a shock 1-0 defeat at home to Championship side Blackburn, but Wenger is adamant that his side are concentrating entirely on Tuesday's tie.

"We are fully focused on tomorrow's game," he said.  "You cannot compare the FA Cup with the Champions League.

"We must focus on our own quality and we have to put into our heads that we have 180 minutes to qualify.

"We have a way to play that everyone in the team knows. We must play with a positive mentality. We know what is important; it's not what people (say), it's what we do on the pitch."

Arsenal midfielder Mikel Arteta was also on hand to echo his manager's sentiments, insisting that he and his team-mates are ready for arguably their most important game of the season.

"We are very positive," he said. "They are a great team, but we are a great team. We are prepared."

The Spaniard went on to talk about slow starts and the opportunity that Tuesday's game brings them to change their fortunes.

"We have a great chance tomorrow to put that down. We want to show we are ready to win this game," he added.

"If you score first, you have a great chance of winning these big games."