Ahead of tomorrow night's return at Old Trafford, we look at the likely key battles.


Messi outshone Cristiano Ronaldo at the Nou Camp and will be looking to do the same at Old Trafford. Like Ronaldo, the richly-talented Argentina star often operates from wide roles but can - and does - pop up to devastating effect in more central positions. He is still looking for match sharpness following a recent injury lay-off, a fact Ferdinand will be hoping to exploit.

Ferdinand lost his cool in Saturday's defeat at Chelsea but it takes a lot to rattle the England defender these days. Formerly prone to regular lapses, the 29-year-old has a new-found air of authority and has both the pace and the stature to contain Messi. Whether the Argentina forward roams in a bid to exploit the slightly less assured Wes Brown or Patrice Evra remains to be seen but Ferdinand can do his part by closing one door on the 20-year-old.


After being booked in the first leg, Hargreaves knows he faces being banned for the final if he is cautioned at Old Trafford. He is set to be risked after starting on the bench at Stamford Bridge, with United aware his destructive capabilities are ideally suited to countering the enviable array of attacking talent at Barca's disposal.

The summer signing from Bayern Munich is likely to be deployed to stem the flow of possession to and from Iniesta, who is a key figure in Barca's system but is sometimes overlooked in deference to his much-hyped team-mates. However, Iniesta himself must be watchful of Hargreaves' occasional bursts forward as well as the threat he poses from close-range free-kicks.


After retaining his PFA Player of the Year crown on Sunday night, Ronaldo has an opportunity to prove himself worthy of the tag against Barca. He vowed to score at Old Trafford after his early penalty howler at the Nou Camp and few would back against him adding to his incredible 38-goal tally this season.

The Portugal star played as a lone striker in the first leg and it is yet to be seen if reverts to a wider role for the return. Of course, he has licence to roam in any case, but if Abidal can shore up Barca's left side it will block the 23-year-old's options and reduce his chances of making a match-winning contribution. But after a shaky season at the Nou Camp, the French defender will have to put in one of his better performances to come out on top.