Brazil also beat Germany five years ago at home, winning a spectacular penalty shootout to win the gold medal.
Thursday’s game took place at the Yokohama International Stadium, the same location where Brazil beat Germany in the 2002 World Cup final.
Everton striker Richarlison’s hat-trick in the opening 30 minutes put Brazil on the path to victory.
However, a late goal from Bayer Leverkusen striker Paulinho capped the victory and gave Brazil a vital three-point opener.
Elsewhere on Thursday, hosts Japan got off to a winning start, beating South Africa 1-0.
South Africa had been exhausted from Covid-19 infections after two players and a video analyst tested positive for Covid-19 in Tokyo on Sunday.
Subsequently, 18 players were identified as close contacts and were forced to self-isolate in their respective rooms in the Tokyo Olympic Village.
A team of 17 South African players, however, adopted Covid-19 pre-match protocols allowing Thursday’s game to take place at the Tokyo stadium.
There were also several surprises in the men’s tournament, with none of Spain, France or Argentina winning their matches.