The Red Devils travel to the Bernabéu on Wednesday night for the first leg of the last-16 tie, fresh from their 2-0 win over Everton on Sunday.
Real Madrid, meanwhile, warmed up for the European showdown with a 4-1 victory over Sevilla on Saturday.
And Alonso feels that blockbuster clashes such as this week’s game bring out the best in the Portuguese coach.
“Mourinho is made for games like this one against United,” Alonso told The Times.
“The way he prepares the game, the way he analyses the opponents, the way he approaches us in terms of giving us a psychological edge and extra motivation, he loves these occasions.
“Everyone is looking forward to it because we are desperate to be in a better mood, a better spirit, after the tie.”