Argentina have crushed Brazil 3-0 to reach Saturday's Olympic football final where they'll play the African giants Nigeria, who sauntered past minnows Belgium.
The defending champion Argentina were inspired by Barcelona's superstar Lionel Messi, who outshone AC Milan's Ronaldinho, to upset their South American neighbours with a brace from Sergio Aguero and a penalty by captain Juan Riquelme.
It means that Brazil, despite being five-time World Cup winners, must wait another four years for a chance to win their first Olympic gold after coming up short twice before in final appearances in 1984 and 1988.
It was a wretched night in Beijing for the Brazilians with Liverpool midfielder Lucas and substitute Thiago Neves both sent off for ugly fouls on Javier Mascherano late in the second half.
In Shanghai, 1996 Atlanta Olympic champions Nigeria proved too big a hurdle for Belgium, comfortably winning 4-1.