Scot insists that players generally concentrate more on the match at hand, as opposed to wanting revenge for a past meeting
The Red Devils met the Blues in the final of the 2008 Champions League at the Luzhniki Stadium in Moscow, and United won on penalties, with John Terry and Nicolas Anelka missing their spot-kicks.
Now the Scot believes that the Blues will be too focused on the task at hand to think of revenge, as he told reporters: "I don't believe players think about revenge.
"Something that happened three years ago goes out of your mind quite quickly.
"The main ambition for any team is to win the cup. The motivation is greater to the match than to think about what happened in the past."