The Portugal international believes United can take heart from several aspects of the performance as they look to eventually win Ferguson his third European Cup success.
"Of course we can win it, why not?" he asked. "We have been doing so well.
"We got to the final and had an opportunity to win and fight against Barcelona to try to win the trophy but it is difficult to play against Barca.
"You never know, next season maybe we'll get to the final again, against a different team. Or even if it's Barcelona, we could win it."
He added: "I think we showed in the first half that it can be done against Barca, we can play against them and score goals.
"But in the second half we left a lot of space in the middle and then they created more chances."