Nani was a product of Sporting Lisbon and the two Portuguese capital sides are bitter rivals.
"I have an extra incentive against Benfica because I used to play for Sporting. The games were like United against City," he said.
"They were always tough. And I always enjoyed it when we won. I hope tonight we can win again.
"I am sure Benfica will play some good football but with a lot of care as well because they are away from home. Their strongest point is the midfield.
"If we are able to control the midfield I am sure we have a good chance to get that positive result we want from the game."