STEPHEN McMANUS today put into some scale the size of the task now facing Celtic if they are to make it a hat-trick of Champions League group qualifications.

Still stunned by losing to Villarreal last night, the skipper lifted his head long enough to look at the double header against Manchester United.

And he summed up just how tough it is going to be to wrest the points they need from United when he predicted Cristiano Ronaldo and Co could go all the way again and retain the trophy they lifted in Moscow only four months ago.

Celtic can take consolation from the fact they gave United a real fright before losing a five-goal thriller the last time the clubs met at Old Trafford.

And they went one better when they defeated the Red Devils at Celtic Park a few weeks later, thanks to a free kick by Shunsuke Nakamura.

Celtic have the belief they are an even stronger side than they were in 2006. But Mick warned: "United are a better team now, too. They won the competition last season and are a top, top side.

"I am in no doubt they can go on and win this tournament again, that is how hard it is going to be for us. But it is a challenge we are willing to take on, and will give it our best shot.

"We will do that in all of the remaining games, that is all anyone can ask of us."

No one could have asked for more effort from Strachan's men during a tough 90 minutes played in hot, humid conditions.

However, despite winning over more of the local fans, they could not find the net -McManus himself had a great second-half chance saved after Gary Caldwell knocked down a corner to him six yards out.

Nor could they keep a clean sheet on the road for what would have been the first time in their group stage history.

So they were denied even a single point to add to the one they took in the opening match at home to Aalborg.

Quickly becoming a veteran of unhappy journeys back from foreign fields - often when Celtic were outplayed much more than they were last night - McManus admitted it doesn't get any easier to take, no matter how well you might have competed against Villarreal.

"It still hurts," he said. "But we can take positives from that game and carry them into the next match against United.

"We are gutted, but it's just one of those things you have to deal with. It gives you no consolation whatsoever that we performed well."

By the time the squad regroup today - they did not get home to their beds until after four this morning - the game will have been consigned to the history books, and the attention will be on United.

McManus will have a key job in helping lift the players again and he started early by saying: "We will take what we did in Villarreal with us when we go to Old Trafford. It has given us something to build on."

The pacy counter-attacking formation unleashed in competitive action for the first time in El Madrigal still needs some fine tuning.

But McManus reckons it got off to a decent start, despite no goals resulting from the system. He said: "We all knew we would play this way away from home. We saw what we could do when we played Porto in the pre-season friendly in Portugal. I think that was the reason we took them on at that time.

"It's a formation we enjoy playing. Only time will tell if can improve in this style the more we use it."