Koeman explained: “We are hindered by the number of players that are injured, I wish I could have all my players available because Manchester United have all their players available.

“It’s interesting that when they beat us the last time we played they had several players out injured and we had all our players available back then.

“The situation has reversed and let’s hope that we can win.”

The Dutchman continued: “We are confident in our possibilities, that is why we have to prepare for the game without thinking too much about the players that are absent.

“For us this is a crucial game. This group has been very level and both group games tomorrow are decisive because any of the four teams can still go through - even United have to win to qualify.”

Koeman believes United should progress, adding: “United are very strong and in theory they should go through.

“Sir Alex Ferguson has a right to say that he is confident his team will progress because he has the strongest team of the group – even if they still haven’t proved it so far.

“We want to play our game and if we can attack, better.

“It’s true that Manchester United have players that can decide a game at any moment but we want to attack and win this game.

“Benfica will fight tomorrow from start to finish – we will not give up because we want to remain in this competition, and if not still be able to play in Europe, which is important.

“In any case it would be a positive thing for us to finish in the top three of the group.”

When asked about the Red Devils being inspired by past performances by George Best against Benfica, the former Dutch international defender said: “History belongs to the past.

“We admired Best and the English admired Eusebio but neither team will be influenced by this in tomorrow’s game.”