It would be a big surprise if Barcelona coach Pep Guardiola strays from the club's traditional, offensive 4-3-3.
Manchester United are less tied to a set formation. Manager Alex Ferguson [ Images ] has frequently used the 4-3-3 to good effect, but if he decides to field Ji-sung on the right he may opt for a 4-4-2.
With a three-pronged strike force of Lionel Messi [ Images ], Samuel Eto'o and Thierry Henry [ Images ], backed by the creativity of Andres Iniesta [ Images ] and Xavi [ Images ] in midfield, the Spanish champions have unrivalled attacking potential. Iniesta's stoppage-time equaliser in the semi-final second leg at Chelsea [ Images ] showed they are also a team that never gives up.
The English champions have an outstanding defence, are a more complete package overall and have that little bit of extra quality on the bench. They can also count on the cunning and experience of Ferguson, arguably the finest brain in world soccer, as well as the determination and confidence the Scot instils in the team.
Barcelona have compensated for fragility in defence this season with their sparkling goal feats, but suspensions to full backs Eric Abidal [ Images ] and Dani Alves and the injury that has ruled out Rafael Marquez [ Images ] leave them looking vulnerable.
They also tend to struggle when Messi and Iniesta are kept under control and Guardiola's inexperience may be exposed when pitted against master tactician Ferguson.
United have shown few weaknesses this season, although they do have less invention than Barca in midfield.
Guardiola will be forced to field a makeshift defence because of suspensions and injuries, which risks aggravating his side's problems with loose marking, especially at set-pieces.
Versatile captain Carles Puyol [ Images ] is tipped to move across to the right flank with Yaya Toure [ Images ] used again at centre back and another converted midfielder, Seydou Keita [ Images ], taking Abidal's place on the left.
United's defence should be at full strength with Rio Ferdinand [ Images ] expected to shake off a calf problem to take his place in the centre alongside Nemanja Vidic [ Images ]. Frenchman Patrice Evra [ Images ], rated one of the top left backs in the world at the moment, is likely be called upon to stop Messi.
United keeper Edwin van der Sar [ Images ] has had a fine campaign and went 14 league matches without conceding a goal between November and February, but Barca's Victor Valdes [ Images ] has not been immune from the occasional error.
Iniesta's ability to shake off a knock will be key to Barca's chances as they are not the same team without the man who's goal against Chelsea put them in the final.
If Sergio Busquets [ Images ] is employed as the holding midfielder he will need to show maturity beyond his 20 years to avoid being overawed by the occasion.
United may have a tad less inspiration in centre of the park, but Park Ji-sung's [ Images ] bottomless energy and Michael Carrick's [ Images ] ability to read the game could swing the match by suffocating the Catalan's sources of play. Ryan Giggs [ Images ] is favourite to come in for the suspended Darren Fletcher [ Images ] with Anderson likely to complete the midfield.
United's defence will need to be at its formidable best to keep out Messi, Eto'o and Henry, who is expected to be fit after a knee problem.