The ex-Liverpool man will be joined by former United favourite Cristiano Ronaldo as the Spanish champions try to overcome a disappointing 1-1 draw at the Santiago Bernabeu in the first-leg between the two in their quest for a 10th European title.
“From the fans’ point of view and because of the history of both clubs, this meeting is pure football,” he told Champions Matchday magazine.
“For Cristiano, who wore the United shirt for many years, it is something even more special. It is for me too.
“When I played for Liverpool the games against United were very intense and important due to the rivalry that existed between the clubs.
“We know it is now a few years since Real Madrid won its last European title, but it is not easy to win this competition because we are facing the best teams in Europe.
“It doesn’t have to become an obsession because this doesn’t help, but yes it is an important objective.”
All eyes will be on Ronaldo as quite apart from his United past, the visitors’ chances of progression would appear to rest on the Portuguese’s broad shoulders and Alonso is confident that the man who has already scored 43 times this season will find the target again at his old stomping ground.
“He is one of the most ambitious players I have known, he has great desire and wants to score a goal in every game.
“His physical capacity and technique is incredible. He is a complete player. He has a tremendous shot, he knows how to beat an opponent in one-on-one situations and how to find space and take advantage of it.”