Roy Keane could return to action as soon as next Tuesday's return leg after Alex Ferguson yesterday said the Republic of Ireland captain's rehabilitation has been accelerated by the use of an oxidisation cylinder.

Ferguson said: "He trained yesterday and hopefully maybe next Tuesday he will be ready. I've been very surprised at his progress, he's remarkable.

"I think the treatment we have given him was different. He spent three days in an oxidisation cylinder, four and half hours a day, and that certainly helped his recovery."