Ronaldo stunned the Portuguese champions with an unstoppable bullet from no less than 35 yards, earning United a hard-fought 3-2 aggregate victory.

"Cristiano Ronaldo's goal was sensational. He played a lone role but did well," Ferguson said after the game.

"I need to think hard to remember a better goal than this one. To start a game with a goal like that is just amazing and the perfect way to turn the tie around."

The Unite boss also paid tribute to Ryan Giggs and Wayne Rooney as he emphasized the reasons behind his side's improved performance.

"Ryan Giggs' experience was crucial and Wayne Rooney's energy was just amazing. It's great to see a player like him on the pitch because he's still so young and never stops for a second," he added.

"There were two main reasons for our improvement when compared with the first game.

"We had some important players back in the team and we had four days to rest instead of the two we had one week ago. That's very important, especially in a competition like this one."

Arsenal Clash

Ferguson is relishing the prospect of grabbing a positive result against perennial domestic rivals Arsenal at the end of the month, in his bid for reaching a second straight final.

"Now we will face Arsenal and it would be great to win the first leg 1-0. They play great football but this is an entirely different clash from the ones in the Premier League. Let's see what happens," the Scot said.

United will face the Gunners three times in less than 18 days, as they clash in the Premiership on May 16th, a few days after their continental double-header.