Benfica coach Rui Vitoria knows their Champions League hopes could be settled tonight.
Manchester United boss Jose Mourinho believes Benfica need to win their remaining group games to reach the knockout phase.
Vitoria said: "It's an important game, we all know that.
"We should never think about the consequences of the game before we play it. This is what we have to focus on. Therefore, we will analyze what may happen, but only after we play it. A high-stakes game.
"It is one of the best teams in Europe, but it does not invalidate our ambition and conviction."