Manchester United defender Nemanja Vidic was absent from the team for this Champions League semi-final first leg after being taken to hospital last night.
Vidic was later discharged after suffering from a stomach complaint but was obviously considered unfit for such a crucial match.
It was a blow for the Serbian, who returned from a knee injury in the 1-1 draw against Blackburn on Saturday.
Manager Alex Ferguson made three changes from that side with goalkeeper Edwin Van der Sar, Owen Hargreaves and Ji-Sung Park all being recalled to the starting line-up.
It was a big night for midfielder Paul Scholes — he was making his 100th Champions League appearance.
Barcelona: Valdes, Zambrotta, Marquez, Milito, Abidal, Xavi, Toure Yaya, Deco, Messi, Eto'o, Iniesta. Subs: Pinto, Gudjohnsen, Henry, Sylvinho, Giovanni, Thuram, Bojan.
Man Utd: Van der Sar, Hargreaves, Ferdinand, Brown, Evra, Ronaldo, Carrick, Scholes, Park, Rooney, Tevez. Subs: Kuszczak, Anderson, Giggs, Nani, Pique, O'Shea, Silvestre.
