Leandro Damiao scored two second-half goals to help Brazil defeat South Korea 3-0 and reach their first Olympic men’s final in 24 years.
Romulo put Brazil ahead at Old Trafford with a first-time strike after a superbly weighted pass from Oscar.
South Korea, who beat Great Britain on penalties in their previous fixture, have the consolation of a bronze medal match against Japan in Cardiff on Friday.
Mexico earned a 3-1 victory over Japan on Tuesday and secure a spot in the final of the men’s Olympic soccer competition.