Despite conceding a crucial away goal, Buttner believes that David Moyes's side can be confident, and was happy with his personal display against one of the most feared attacks in Europe.
"Of course we can do it. We always believe in ourselves," the Dutch defender told Sky Sports News. "We had chances to score more goals and we have to focus on that. Defensively we did well, we didn't give a lot away, just a goal, and I think we have a good chance.
"It was nice to play. For me it was my first big game and I think I did well."
United travel to the Allianz Arena for the second leg next Wednesday.