Arsenal have a defensive crisis ahead of the showdown with Chelsea with both Kieran Gibbs and William Gallas injured.

The Gunners responded from their lacklustre defeat to Sunderland with a comfortable Champions League 2-0 victory over Standard Liege, a win which secured safe passage into the last 16 at the top of Group H ahead of the final match in Olympiacos after first-half goals from Samir Nasri and Denilson.

However, it came at a cost as centre-back Gallas went off at the break with a combination of an ankle problem and a lump above his eye following a clash of heads with Andrey Arshavin, which also left the Russian needing staples to close a bloody gash.

Gibbs, meanwhile, limped out during the closing stages following a hefty challenge from Eliaquim Mangala.

The England Under-21 full-back had only just returned to fitness from a injury to his right foot suffered while away on international duty, and Arsenal have confirmed Gibbs had suffered a fracture to the first metatarsal on his left foot, and would undergo surgery which is set to rule him out for at least two months.

"Gallas has an ankle problem and a swollen eye. I think he will recover from the eye, and from the ankle we hope so [in time for Chelsea]," said Wenger, speaking immediately after the match.

"Gibbs is much more serious.

"It was a very bad challenge, and it was not the player's first try.

"We have to X-ray him and I think he has gone to hospital to check because he has a big hole in his leg.

"He doesn't look too good, and that is unfortunate."