Lionel Messi struck a superb stoppage-time winner to give Argentina their first victory over Brazil since June 2005.
Brazil, looking to build on promising early results under their new coach Mano Menezes, were the strongest side for most of the match which was staged in Qatar, but they could not stop Barcelona superstar Messi from pinching the late glory.
Messi collected Ezequiel Lavezzi's clever flicked pass before slaloming past four defenders and stroking the ball home into the bottom right corner of the net.
Although Diego Maradona tried to fit the Toon star into his side - even if it was at left-back - Menezes hasn't been too keen on picking the winger in recent games.
Argentina: Romero; Zanetti, Pareja, Burdisso, Heinze; Banega, Mascherano, Pastore; Messi, Higuaín, Di María.
Brazil: Víctor; Dani Alves, Thiago Silva, David Luiz, André Santos; Lucas, Elías; Ramires, Ronaldinho; Robinho, Neymar.