Brazil, who exhibited one touch football with swift short passes, dominated the match throughout at the Nehru Stadium.
They scored through Paulo Henrique Sampaio Filho(24th), Vinicuis Jose paixo de Oliveira Junior(35th), Victor Gabriel Moura de Oliveira(40th, 61st) and Alan de Sourza Guimaraes (90+1).
South Africa, who were always on the receiving end, pulled one back through S'miso Bophela in the 89th minute.
Brazil, who beat South Africa 3-0 in the league stage, made their intention clear from the start as they came with a flury of moves but Alan Guimaraes, Paulo and Victor failed to find the back of the net.
The South Africans found the going tough and had a few close shaves. They nearly succeded in taking the lead in the 20th minute but Ndamolelo Radzilani, in front of an open goal, saw his shot hit the cross bar.
Brazil retaliated and took the lead four minutes later. A swift move on the right saw Marcos Antonio Santos put a through pass to Paulo Henrique Filho, who beat rival keeper Glen Baadjies, with a neat placement.
South Africa had a glorious chance to equalise when defender Mswati Mavuso sent a goalmouth cross, but Sithembiso Kurata and Tyreese Pillay failed to tap the ball into an open net.
Thereafter, Brazil mounted pressure and scored two more goals to lead 3-0 at the break. Vinicuis Jose Paixao de Oliveira junior, who saw the keeper come out of his charge, lobbed the ball over him into the net from top of the box in the 35th minute.
Five minutes latter Brazil earned a penalty after defender Nikanyiso Shinga handled the ball inside the box and referee R Venktesh gave the penalty, which Victor Gabriel Moura de Oliveira converted.
Alan de Souza Guimaaraes, who was a livewire in the midfield, led the charge and kept the personnel upfront busy with a steady flow of passes.
Victor Gabriel Moura de oliveira scored his second in the 62nd minute when Alan laid the ball to him from inside the box in the 61st minute after getting the better of two rival defenders.
South Africa pulled one back when S'miso Bophela's left footer from inside the box brushed rival keeper Arthur Gazze de Souza's fingers and went in. Brazil's Alan de Sourza Guimaraes rounded the tally with a powerful longranger in the injury time.