We gave the Germans too much room in the midfield tonite. And German football usually use the midfield as a direct key in the offensive part of the game.
If Manchester United want's to win in Germany they have to close that gate. Whomever wins the battle on the midfield will win the game.
And I can't see that happen with 4 players (which is even more true due to Beckham's injury). So the answer must be a midfield with 5 players.
What makes it risky is that we must go for the throat. I don't think defensive tactics will help us much against Leverkusen, because they seem very able to punish any defense anyhow. So we must kill them. Which means just putting the ball in the net many times. And keep the offensive momentum going. Which is the football we like to play anyway.