Los Rojiblancos head to Old Trafford on Tuesday evening with the aim of making it through to the last eight of the European Cup for the first time in six decades.
United are considered the favourites following last month's stalemate in the reverse fixture, but Montella - brought in to replace Eduardo Berizzo after the group stage - is confident that his side can snatch victory if they net an away goal.
"It's a special match because we can reach the quarter-finals," he said at his pre-match press conference. "It is special for me and for the club because it has been 60 years that the team has not been able to play in that round. We need to score one goal, and at home, we had the opportunities.
"It's going to be tough, but we have confidence. We know that we play against a great team, with a great coach, players and a historic club. We have to be at our best level and be able to compete. It is a game that we must interpret every situation, defending and attacking when necessary."
Only Porto (15) have conceded more goals of any side remaining in the competition at the last-16 stage than Sevilla (12).