The Portugal winger ran from deep to get on the end of a chip from Paul Scholes and score with a brave header to stun Roma on Tuesday night.

It was Ronaldo's 36th goal of the season and United went on to defeat the Italian title-chasers 2-0 - with Wayne Rooney extending their lead.

Sir Alex Ferguson's side are now in the driving seat going into the quarter-final second leg at Old Trafford next Wednesday.

Ronaldo has taken his great domestic form into the European arena and now scored seven goals in eight games.

However, he can recall little of his latest effort as he was left dazed and needing brief treatment.

Ronaldo said: "To be honest, I don't remember much about the goal.

"I went down and I felt pain. I didn't enjoy it.

"But I will have time to watch it on television - others say it's a good goal."

United look poised to face Barcelona - 1-0 winners against Schalke in Germany - in the semi-finals and Ronaldo is calling for a repeat performance against Roma at Old Trafford.

He said: "To win 2-0 away is a great result for us. But it is wrong to think that it's all done.

"However, we have the return leg at home and we have a chance.

"If we carry on like this and play well at home, we will get there.

"I think the second goal killed the game off. We had several chances after to score more goals but a 2-0 win is a good result.

"It's always important not to concede goals and to keep a clean sheet as it is good for confidence."

The only downside for United was a knee injury sustained by defender Nemanja Vidic.

The Serbia international was due to have a scan today to assess the extent of the problem.

Vidic came off in the 33rd minute and was replaced by John O'Shea, who slotted in well at the back alongside Rio Ferdinand.

O'Shea has made only nine Premier League starts this season but his composed performance was applauded by fellow defender Patrice Evra.

"It was important to keep a clean sheet and we did our job," said the Frenchman.

"We have a big squad and John showed how strong it is when he came on and filled in for Nemanja. We have confidence in whoever plays."

O'Shea savoured the experience at the Stadio Olimpico.

"We can be very proud of what we achieved in Rome," he said.

"It's not easy to play away from home and get a good result but we have done this.

"I think it's amazing how the team has played and the confidence we have shown throughout the game."

"We have taken a step in the right direction and now we must make sure to clinch qualification at home next week."

United boss Ferguson has urged caution ahead of the second leg.

He said: "At this moment, it is a fantastic result for us.

"But probably on the day of the game I will start to worry about it.

"The first thing we have to do is prepare properly for the match.

"We cannot take anything for granted with a place in the semi-finals at stake."