In their 14 meetings, Manchester United chief Fergie has beaten the Special One twice, lost six times and drawn six times.
Real striker Benzema said: "I am sure there is something personal for Mourinho.
"When he was in England, every season he was fighting with Alex Ferguson for the title.
"Mourinho is a big winner and wants to win every game.
"But you can see what these games against Manchester United mean to him.
"There is an excitement is his voice."