Yet there is little doubting about the biggest matchup of them all—Premier League leaders Manchester United traveling to the Bernabeu to take on reigning Spanish champions Real Madrid.
And the matchup between two legendary coaches of the game, Sir Alex Ferguson and Jose Mourinho, will be particularly interesting to watch unfold.
Both have their respective claims of being one of the greatest managers in world football, and both will have been working through their plans for this one a long time in advance.
So how will they pay off? Will Fergie's midfield diamond work against the Spanish dominance in central midfield, or will Mourinho come up with a plan to stifle the likes of Wayne Rooney and Robin van Persie working well together in the Red Devils' attack?
Neither manager particularly likes the other, and they will both be desperate to gain a win here. Expect plenty of fireworks and plenty of drama, which can usually be expected when either Mourinho or Ferguson's team take the pitch.
The fact they come up against each other almost guarantees something special.
What matchups are you most looking forward to in the UCL?
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