Ronaldo scored the equalising goal in the first leg at the Santiago Bernabeu, and while much has been made of the Portuguese's return to Old Trafford, Ferguson has called on his current players to play their own games.
"What do you expect when you play against a team with Ronaldo in it? You expect problems during the night, and we'll have to try to curtail that as best we can," he told reporters.
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"As we know, I believe they are one of the best counterattacking teams in Europe. That showed itself last Tuesday at Camp Nou [when Madrid beat Barcelona 3-1], they were absolutely stunning. We've got to find a way of coping with that but posing an attacking threat also.
"If you're preparing for a game at any level you have to pay respect to the strength of the other team, which we do. We look at their dangerous players and tactics. That applies itself tomorrow, we also know about the strength of our own team and where we are. We know our strengths and our pattern of play and hopefully it helps us tomorrow."
Ferguson also confirmed that Phil Jones will miss the game with an ankle injury.
The 21-year-old, who played a key role in the first leg, limped out of the FA Cup game against Reading in February and has lost his race to be ready for the return.
"He's not fit. He won't be fit for [Tuesday]," the manager continued.
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Ferguson believes Madrid will score at least once on Tuesday, and told fans to expect a great spectacle.
"It's a massive build-up, you can see the amount of cameras at the training ground, that gives you some indication," he said.
"I think that both teams are in form. Real have had two fantastic performances against Barcelona, I saw the first one and they played very well. They've found form at the right time, whereas our form as been consistent for quite a while. As a European occasion I don't think you get bigger than this. It's set up to be a marvellous game and I don't think it will be a disappointment.
"I think there'll be goals, I think both teams will score. We have to think that we can score more than one."
When asked about the possibility of Jose Mourinho succeeding him at Old Trafford, Ferguson was in no mood to discuss his future.
"It's impossible to discuss who is going to replace me because there is no time-frame on it."