Jose Bosingwa - Lionel Messi
This is the one that has the English press all a-flutter before the Blues' encounter at Camp Nou. The 26-year-old Portuguese is set to line up at right-back, and with Messi perhaps slated to play on the left, there could be a lop-sided battle in the works.
Some have questioned whether or not the former Porto man has what it takes to deal with the pace and footwork of Leo, and although Bosingwa is certainly tough in the tackle and possesses a great physique, his close-work does leave something to be desired.
What may occur is that Messi will switch flanks with Thierry Henry at times, making a man-marking job all the tougher but also giving Bosingwa a bit of a break.
Even more important, though, is the prospect of doubling-up. The centre-back who starts next to Bosingwa, be it John Terry or Alex, will be expected to narrow Messi's angles. This neutralises the Argentine to some extent, but that raises a problem of its own...
Michael Essien - Xavi
An intriguing personal battle may be between Essien and Xavi in midfield, and that's largely because Chelsea's centre-backs are set to be so heavily occupied that they could miss the Catalan's forward runs.
Xavi has been in and around the goals this season largely due to that most deadly of weapons: the cut-back. If one looks back to Barcelona's win over Sevilla two weeks ago, they will remember that the men doubling up on Thierry Henry completely missed the Spanish international's run towards the edge of the box. Unmarked, it was a case of picking his spot for Xavi to net.
This means that Essien, who will be playing a very much defensive role, is going to have his hands full. Xavi's movement off the ball is an underrated aspect of his play, and given the near-telepathic interplay between himself, Iniesta, Henry and Messi when Barcelona are on song, this is a source of real concern.
On the other hand, Essien can take heart from the fact that Xavi struggled against Valencia at the weekend, while the Ghanaian himself was rested against West Ham.
Essentially, if the centre-backs do not track midfield runners well enough, Essien is going to have his hands full. If they do keep Xavi on a leash, he can look forward to a sedate evening and use his attacking skills, too.
Didier Drogba - Gerard Pique
Former Manchester United stopper Gerard Pique will have a nodding acquaintance with Didier Drogba from his time in England, but it's the Ivorian who will be predicted to be top dog in this battle.
Playing a very much central role by himself, Drogba's threat will come as much in the air as anywhere else. (Contrast this to the other end of the pitch, where Samuel Eto'o will face extremely stiff competition to win an aerial battle against either of Terry or Alex). Pique thus faces a struggle to maintain his positioning and also win high balls.
The former Marseille man will be Chelsea's man goal threat, and even with Carles Puyol sweeping up, he could be a lot to handle.
Ewan Macdonald, Goal.com