Defence was key to victory

Sir Alex Ferguson cited the welcome return of a solid foundation as United claimed a slender but significant victory in Portugal.

Rio Ferdinand and Nemanja Vidic earned much of his praise as they played 90 minutes together for the first time since the Reds overcame Inter 2-0 in the previous round of the Champions League - also the last occasion when United kept a clean sheet.

"I think the stability at the back, the recognition of Ferdinand and Vidic together is always a great start for your team," said Sir Alex after winning his 150th Champions League match.

"There was a lot of good concentration at the back, the team defended very, very well and I think that was key to it really. If we can get back to that foundation of not giving goals away, then we can do well."

United had an aggregate lead to defend from as early as the sixth minute at Estadio do Dragao, thanks to a glorious goal by Cristiano Ronaldo - arguably one of the best of his illustrious career to date.

"It was unbelievable, a magnificent hit, absolutely fantastic," enthused Sir Alex.

"The shot took them all by surprise, coming from 30 yards or whatever it was. The goalkeeper had no chance really."

The boss went on to clarify the content of a recent conversation with Cristiano. "The point I made to Ronaldo was to keep the referees on his side and not turn them against him.

"He's expecting a foul (to be given) every time. He's the best player in the world, he's going to be fouled and sometimes the referee's going to err on the other side. He's just got to accept that. If he does that, then he's a great player."

Another great player who performed well on the night, albeit without grabbing the headlines, was Wayne Rooney. The striker operated in a selfless role on the right flank and earned the manager's praise for his "engine and appetite."

"You can ask some players to do a certain role in a game of football because they have a certain desire and an appetite. Wayne's got that."

Turning his attentions to the next challenge in Europe, and the prospect of facing Arsenal at Old Trafford and then the Emirates, Sir Alex said:

"An all-British semi-final adds a certain spice to the tie. It’s two good football teams - the game at the Emirates earlier in the season was a fantastic representation of the way football should be played.

"It should be a terrific semi-final and we’re looking forward to it."