Sir Alex Ferguson is counting the cost of a pulsating encounter with Celtic as Manchester United side kicked off their Champions League campaign with a thrilling 3-2 victory at Old Trafford last night.

But the United manager saw Ryan Giggs limp off with a hamstring injury which will keep him out of action for up to four weeks. That came hard on the heels of the news that midfielder Ji-sung Park was due to undergo an ankle operation today which will sideline him for three months.

It leaves Ferguson desperately short in the midfield area, despite Paul Scholes returning against Celtic with a performance which brought praise from his manager.

Ferguson said: "The injuries are a blow - but for me, Scholes was the man of the match. He is just fantastic, and his passing won us the game. Wayne Rooney showed he needed a game, but Scholes at 31 has phenomenal composure and passing awareness."

Ferguson also praised striker Louis Saha, who scored twice - once from the penalty spot after Celtic goalkeeper Artur Boruc was adjudged to have brought down Giggs.

The United boss said: "Louis Saha could have beaten the scoring record in Europe. He was fantastic. We have a lot of teams who come here with five at the back - but at least Celtic had a positive nature to them.

"Having said that, we could have scored 10. We had some slack finishing, and Artur Boruc made some fantastic saves."