It's not just Manchester City vs Real Madrid. It's also the champions of England vs the champions of Spain and it's also rich club vs rich club.
Most of all though, it's Cristiano Ronaldo's return to Manchester.
Jose Mourinho has already given his verdict: "I think they can win tomorrow, of course they can, and they can also win in Dortmund, why not, but eight points is not enough.
However, he did tip them as future champions: "I think they are a team to win the competition - one of the teams to win the competition."
No doubt City manager Roberto Mancini will also have an eye on the Chelsea EPL game on Sunday, but it may be silly to think that he will throw in the towel against Madrid. Not when he knows his players almost won at the Santiago Bernabeu earlier in the season. Also Man City have the comfort of playing at home where they've lost just once in almost two and a half years.
Both teams have changed their formations only once all season — when they met each other in the previous group fixture.
Here are the key player battles that could determine the outcome of the match:
Maicon vs Cristiano Ronaldo: Maicon changed the team's outlook when he came on recently against Tottenham Hotspur. He also played in the 5-0 thrashing of Aston Villa and is most likely to start against Madrid. His pace and strength make him the perfect ploy against Ronaldo — himself a player who relies on his pace and trickery to get past men. If Maicon can maintain his position and thwart Ronaldo's inward runs, then Madrid will find it hard to break City down. On the other hand, Ronaldo is as usual on fire — he has scored five goals in four Champions League games and 21 in 23 total games. Unbelievable.
Alexander Kolarov vs Angel di Maria: Gael Clichy is injured, so that means Kolarov should fill his place. Di Maria has played 12 La Liga games and four Champions League and should ideally play, unless Mourinho opts for Jose Callejon. Either way, Kolarov is more a wing-back than a solid left-back and will leave spaces open when he goes forward. He likes to take a pop from distance now and again and is forward during set-pieces which means Di Maria can make City suffer on the counter.
Gareth Barry vs Mesut Ozil: Ozil has four appearances, one goal and two assists in the competition. Overall, he has the most number of assists in the team and his creativity has come to the fore when Kaka and Luka Modric are on the bench. He can skip away in an instant, sail past defenders and has an ability to slide passes from tight areas. Against a team like City, who rely heavily on their defensive midfielders, you will certainly need an Ozil. On the other hand, Modric and Kaka aren't that bad either, but may not start.
Carlos Tevez vs Pepe: It's not going to be easy to stop Tevez. He has been an inspiration since he gave up golf. In the EPL, he has six goals and seven assists and is usually the man behind Aguero's freedom to roam forward. Aguero may come off for super-sub Edin Dzeko, but Tevez will stay on. He has the doggedness to rattle Pepe, who is known as one of the most rash tacklers in the game. But with the bulldog around, Pepe will need to take care.
Yaya Toure vs Xabi Alonso: Toure has been allowed to roam forward this season, and even though his form has not been stellar, he has what it takes to get past Alonso. Alonso, while an excellent ball player, relies more on Sami Khedira to back him up in midfield to win tackles. But he can make Yaya run around with his passing range. That's the key to winning for Madrid — burn out Yaya. But for City, they can afford to let the big Ivorian forgo his defensive duties and support the forward-line.
The other big battle is certainly that of the mind — Jose Mourinho is set for his 100th Champions League match and Roberto Mancini has enough experience to devise a plan to thwart Madrid. The two goalkeepers, Iker Casillas and Joe Hart are among the best in the world currently and will have Aguero and Karim Benzema to cope with.
This match is big... and the group is still open. As they say, may the best team win.