Ferguson has had to hold Rooney back following the striker's recovery from the fractured foot he sustained in the opening-day Premier League draw with Reading.

Rooney even battered on Ferguson's door on Friday, cup of tea in hand, demanding to play at old club Everton 24 hours later.

On medical advice, the United boss rejected the demand but included Rooney in his squad as they begin their latest Champions League quest.

Now Ferguson must decide whether to start with the England man at the Jose Alvalade Stadium or persevere with Carlos Tevez, who is yet to score since his arrival at Old Trafford, or hand Louis Saha a recall.

"It is not an easy one because none of our three strikers are at 100% of the level you would want for European football," he said.

"Carlos is getting better but he will only reach the level we want by good training. We are trying to gauge Louis. He has been out for eight months, so the plan was to ease him in the way we are doing.

"And Wayne has only had one game, which is a month ago now.

"Basically, I have to decide whether to start with Wayne, or do what I did on Saturday by playing Carlos with Ryan Giggs and then bring Wayne and Louis off the bench. I want to get it right because I want to win the game."

Ferguson needs no reminding it was a win in Lisbon, against Benfica, which launched United towards the semi-finals of last season's competition.

A hefty defeat eventually arrived in the second leg of their last four tussle with AC Milan, a result Ferguson blamed on an acute lack of bodies after United were struck down by an ill-timed spate of injuries.

The Old Trafford chief has attempted to ward off such a problem this time around by not letting quite as many of his promising youngsters leave on loan.

Yet, it is also a fact that Milan had long since abandoned any hope of winning Serie A, a situation which also applied to fellow finalists Liverpool, and Arsenal the year before.

However, Ferguson dismisses the theory it is not possible for a club to contest the major prizes both at home and abroad.

"It can be done," he said.

"We came quite close last year and I have said many times, the thing that let us down in Milan was the lack of freshness due to the same players having to play in so many games.

"Although we don't have our full squad available at present, we have tried to guard against the same situation and the young players we have retained will give us a far better support system."

Nevertheless, Ferguson will be forced to name a hefty contingent of youngsters on the bench tomorrow.

As expected, Owen Hargreaves remained in Manchester for further treatment on his thigh injury, while Mikael Silvestre, John O'Shea, Darren Fletcher and Gary Neville are part of a lengthy injury list which also includes long-term absentees Park Ji-sung and Ben Foster.