It is another busy night of Champions League action tonight with certain groups more tightly poised than others.

Arsenal travel to Borussia Dortmund, knowing that defeat would be a severe blow to their chances of reaching the knockout stages.

Jack Wilshere, Theo Walcott, Alex Oxlade-Chamberlain, Mathieu Flamini and Lukas Podolski remain on the sidelines.

However Kieran Gibbs has recovered from a muscular problem which saw him substituted against Liverpool.

Arsene Wenger will hope his team can deal with transitions more effectively than they did in the 2 - 1 defeat in the Emirates where Dortmund hit the Gunners on the break and collectively ran 11km more than the Premier League leaders.

Celtic are in Amsterdam to face Ajax in Group H. The Hoops beat the four-time champions two weeks ago to give them a small chance of reaching the knockout stages.

Celtic are two points behind second-placed Milan who face Barcelona tonight. A win for Celtic, coupled with a Milan defeat would put Neil Lennon's team second in the group.

Celtic captain Scott Brown is suspended as he is still serving a three match ban.

Chelsea hope to take another step towards the second round in their Group E clash with German opposition.

Fernando Torres will sit out Chelsea's home tie with Schalke tonight.

The Spanish striker has a muscular injury.

The Blues and tonight's opponents are both on six points in Group E, although Chelsea did beat Schalke 3 - 0 away two weeks ago.

Manager Jose Mourinho could be tempted into changes as he continues to work out what his best team is.