JAMES FORREST has emerged from a "nightmare" illness and is ready to take on the burden of helping Celtic to a "must-win" victory over Ajax in the Champions League tomorrow.

The Scottish internationalist spent five days in hospital last month with what was believed to have been a respiratory virus but the 22-year-old said subsequent tests failed to reveal the precise cause of his illness.

"They didn't actually say what it was in the end. It was a nightmare. It was my head and it was terrible. I don't really want to talk about it. I feel better now and I just want to look forward," said Forrest who scored a spectacular equaliser away to Hibernian in the 1-1 draw on Saturday.

He added: "I lost a lot of weight and I've been trying to build myself up for the last two weeks. That's me put most of it back on, so I just need to play more games and get fit that way. It's great to be back and I feel much better. Hopefully I can start to get more minutes on the pitch."

The slightly built winger, who lost a stone during his illness, has been regularly injured, with a sciatic nerve proving a persistent problem.

With Scott Brown missing the Ajax match through suspension, his return to the first team will be a relief for Neil Lennon, the Celtic manager, as the Prestwick youngster replaced Kris Commons, capped 12 times for Scotland, who came off in the first half on Saturday with a hamstring strain. "I am happy to take on extra responsibility if Kris is out," said Forrest. "But we also have guys like Sami [Georgios Samaras], [Anthony] Stokes and [Teemu] Pukki. I've played in big games before and I'm looking forward to it. All the boys will tell you the atmosphere is frightening. We want to give something back to the fans for their support. We want to give them something to cheer about."

Forrest is convinced Celtic need a victory. "Is it a must-win game? We need to get three points and we have the players to do that," he said. "We played Ajax in pre-season last year and they were very good. They pass it well, they have a lot of pace and they need the points. We expect them to attack."