The Parkhead side arrived in Manchester looking for their first away win in the tournament but face a United side who ominously moved in to the top four in the Barclays Premier League for the first time on Saturday with a convincing 4-0 home win over West Brom.

Celtic lost 3-2 at Old Trafford at the same stage of the competition two seasons ago but a 1-0 win in the return game in Glasgow took them through to the last 16 of the tournament for the first time.

However, Strachan believes Sir Alex Ferguson's side have improved since then and he is under no illusions as to how difficult it will be to get any sort of result against his former club.

"We are going to play the best team in Europe," Strachan said.

"They are the champions of Europe and the champions of England and they have some of the best players in the world.

"I don't think they were English champions two years ago but they are now and they are European champions as well.

"The younger players in their side have two years more experience and the more you think about it, the scarier it gets.

"You have to face Manchester United with ability, pace, strength, height and character.

"Trying to find all those things in eleven players is very, very hard

"But the players know what's coming and they are looking forward to the challenge.

"A lot of them played here two years ago and they enjoyed the experience.

"It's in the traditions of both clubs to attack and try and entertain so we will do our best.

"A lot of teams come here and say that but traffic seems to go the one way.

"I've heard people saying that they are sitting in at Old Trafford.

"No they're not - they just can't get out. There is a difference."

Strachan tried to inject some humour in to yet another question about him facing up to Ferguson, whom he played under for Aberdeen and United.

"If we are playing one-for-one in the middle of the park then I'll beat him," Strachan joked.

"I'm fitter than him, there's no doubt about it.

"He wasn't a good defender and I was quite a good attacker so it will be no problem.

"So if it was me and him playing tomorrow then I would be delighted.

"But unfortunately he has a lot of world class players behind him.

"Fortunately for me, I have a lot of players who want to get better so it should be a good challenge."

Strachan was more serious discussing the depletion of his squad through injury.

Target men Jan Vennegoor of Hesselink, Georgios Samaras and Chris Killen are all out as is Spanish midfielder Marc Crosas.

However, it appears that defender Gary Caldwell, who was substituted in the 2-1 win over Inverness Caledonian Thistle on Saturday needing stitches in an ankle wound, will make it.

Strachan said: "At Villarreal in the last Champions League game, for the first time since I've been manager, I had a system in which I was confident that everyone could play.

"At the moment, we have to rethink that because of injuries.

"We have been hit by a few injuries in very important areas and we are waiting on Gary Caldwell to see how he is.

"He has a determined streak and he really shouldn't have gone back on in the second half in Inverness but he wanted to make sure we won the game and make sure he is in the team for Manchester.

"I know Gary and if he can be there, he will be there."