Bayern Munich v Arsenal: Olympic Stadium 7:45  This evening Arsenal enter a 16-day stretch that will go a long way to shaping their season. Lose to Bayern Munich in the UEFA Champions League and Sheffield United in the English FA Cup and there promises to be an unusually slow spring for Arsene Wenger's squad.

At a snowbound airport in Munich last night, Patrick Vieira emphasised the players are thinking on very different lines.

The midfielder insisted the treble was still a target, and rejected suggestions that Arsenal's defence of their league title is over and that another season of failure in Europe can be taken for granted.

The captain seems confident this will not be a fallow year at Highbury. "I still believe we will be successful this year," Vieira said.

"We are still in the Premiership and Champions League, and the FA Cup is a competition we want to be in as well. We will see what happens at the end of the season, but I'm sure we will be successful."

Arsenal are no strangers to domestic triumphs, but Champions League glory has so far eluded them and tonight's first leg at Bayern is a key test, especially in Sol Campbell's absence. Two quarter-finals over the past six seasons do not accurately reflect the talent, and it has been an irritation.

"The Champions League is really important for us as a team," Vieira said. "I feel a little bit frustrated because we always feel we can do better than we did. But what's important is to improve every year and that's what we will try to do. We have learned a lot in the last few years and it's time for us to show that."

Vieira suggested the team were more tactically aware now of the balance between defence and attack. Yet, if Arsenal left themselves too open away in Europe in the past, there have been signs this season that they have retreated too much into their shells when ahead on their travels, with leads surrendered at Rosenborg and Panathinaikos. Perhaps in their determination finally to crack this competition, Arsenal have appeared too tense at times.

"It's important to find a good mixture between motivation and being relaxed," Wenger said. "If you are not relaxed you don't play well.

"There's only one thing that's important - that we play at our level. If we play at our level I know we have a very good chance to win the game."

Arsenal's six-game unbeaten run away in Europe will get its most serious test from a Bayern team likely to be without the injured Michael Ballack.

Edu's return alongside Vieira ought to help the protection of a weakened back four. Ashley Cole will be assessed today after flu and gastroenteritis.

"He's been a week in bed, but today he was a bit better," said Wenger.

Plenty of attention will go on the goalkeepers, Jens Lehmann and Oliver Kahn, long-standing rivals. The Germany coach, Jurgen Klinsmann, is due at the game and Lehmann expects to be booed by the Bayern fans.

"It's Arsenal against Bayern Munich, not Kahn against Lehmann," said Wenger, who is confident Lehmann will thrive on the pressure. "Usually it brings the best out of these players. They love the pressure. It's harder for them to play a game without pressure."