Ronaldo's sixth-minute goal, a stunning right-footed strike from 40 yards, was enough to seal a 3-2 quarter-final aggregate win and confirm an all-Premier League last-four meeting with Arsenal. With Chelsea also through after defeating Liverpool, it means that for the third season in a row, three of the four semi-finalists are English.
It was Ronaldo's first away goal in the Champions League since last season's final against Chelsea in Moscow and the World Footballer of the Year insisted that last night's strike was as good as any he has scored. "When Anderson gave me the ball, I thought straight away to turn and shoot at goal and I scored a fantastic goal," he said.
"It's the best goal I've ever scored. I've just seen the replay and I didn't realise it was 40 yards out and I hit it at 65mph - wow! This victory will give us confidence. The last five games we didn't play great, but I hope this will change that.
"It's a fantastic tie for us in the semi-final because Arsenal play fantastic football. We know them well, but I think we can win the tie and go to the final."
United manager Sir Alex Ferguson must now prepare for a first leg against Arsene Wenger's team at Old Trafford on April 29 and the Scot has challenged his players to take a lead to the Emirates for the return leg. He said: "No matter what happens, the semi-final is going to be a big factor in our season now. With it being an all-English tie, it will certainly give it extra spice.
"I'd be quite happy to win the home leg 1-0. That would be a perfect scoreline for me. The league game at the Emirates earlier this season showed football in a great light. It will be a terrific tie."
Tues Apr 28 Barcelona v Chelsea
Wed Apr 29 Manchester United v Arsenal
Tues May 5 Arsenal v Manchester United
Wed May 6 Chelsea v Barcelona
Sat May 27 Stadio Olimpico, Rome.