The Wizards defeated United today 2-1 in front of a record crowd.
Nani said: "Their entire team played very well today. They played with a lot of motivation because they played Manchester United.
"It's difficult to compare them directly to Barcelona because they're one of the best teams in the world to play that kind of football, but they play very nice and quick and they passed the ball well like a quality Spanish club. Their style was good."