Reigning English champions Arsenal, second in Group E, face bottom side Rosenborg of Norway at Highbury on Tuesday knowing a win will put them into the knockout stages.

However, a draw or a defeat will mean Arsene Wenger's team could lose out to Greek side Panathinaikos who will sneak through if they beat PSV Eindhoven who have already made it through to the next round.

On Wednesday, Liverpool know a 1-0 win against Group A leaders Olympiakos at Anfield will be good enough to see them through with any other margin of victory at the mercy of UEFA's complicated qualifying criteria.

Second-placed Monaco, who beat Liverpool 1-0 last month, face Deportivo La Coruna knowing that if Liverpool fail to win, they could afford to lose in Spain and still qualify.

Real Madrid, nine-time European champions, go to eliminated Roma in Group B where a win will put them through but if the Spanish giants only draw in Italy, then Bayer Leverkusen will join Dynamo Kiev in the next round if they draw against the Ukrainians.

Arsenal will be without skipper Patrick Vieira, who was sent-off in the 1-1 draw at Eindhoven last month, so fellow French international Thierry Henry will lead the side.

Arsenal will also feature 17-year-old Cesc Fabregas and Mathieu Flamini, a 20-year-old who has never started a Premiership or a Champions League match, in the middle of midfield.

It remains to be seen whether Jens Lehmann will regain his place in goal at the expense of Manuel Almunia who kept a cleansheet in the 3-0 weekend win against Birmingham.

Lehmann has endured a number of European nightmares and was at fault for both goals in Arsenal's 2-2 draw at Panathinaikos this season.

"I have a great respect for Jens Lehmann, he is 100% professional, he just needs a breather," said Wenger who admits his side still have it all to prove in the Champions League where they never made it beyond the quarter-finals.

"We cannot think 'OK, it will be easy', because in the Champions League, unfortunately, for us it has never been easy," he said.

"I feel that they are a team with a great experience in the Champions League as well, and usually they are not frightened to play football."

Liverpool's campaign suffered a setback when they lost 1-0 in controversial circumstances in Monaco last month where they claimed Javier Saviola's winner was handball.

Bur Liverpool boss Rafael Benitez is confident that Anfield's passion for European nights will see them through.

"Olympiakos is a very big game. When you play Champions League you know all the games will be difficult, but this one is the most important so far because if we win we qualify," said Benitez.

"Some people say that having to win 1-0 or by two clear goals will be difficult, but if you told me before the group started we'd be playing Olympiakos at home needing a 1-0 win to qualify then I'd have signed up for that."

Real Madrid go into their game in Rome knowing a win will take them through.

England striker Michael Owen, with five goals in the Spanish League this season as well as one in Europe, has happy memories of the Olympic Stadium in Rome having played their with Liverpool.

"I played two consecutive seasons against them and I scored two goals there," said Owen.

"I remember I had played several games without scoring, I was having a bad patch and those goals were a turning point - I won the Golden Ball."

Juventus, Bayern Munich, Manchester United, Lyon, PSV, AC Milan, Barcelona, Inter Milan and Chelsea have already made sure of their second round places but defending champions Porto and Valencia, Champions League runners-up in 2000 and 2001, could be knocked out this week.

In Group H, Porto face Chelsea, now managed by former boss Jose Mourinho on Tuesday, and they need to win and hope that Paris St Germain draw with CSKA Moscow. The Russians can also make it if they beat PSG and Porto fail to beat Chelsea.

In Group G, where Inter have already made it through, Valencia can progress if they beat Werder Bremen 1-0.