The 35-year-old, who has scored 111 international goals and has been named FIFA World Player of the Year six times, opened the scoring in the ninth minute before adding a second goal in the 74th minute.
Debinha, Andressa Alves and Beatriz scored the other goals as Brazil eased to victory in their Group F match in Rifu, Japan.
Marta’s brace means she now has 12 Olympic Games goals to her name, having scored her first in Athens in 2004, and is now just two shy of the all-time record held by her compatriot Cristiane.
She wasn’t the only one of Brazil’s players to make history on Wednesday though, as her 43-year-old teammate Formiga also created some Olympic history of her own.
The Sao Paolo midfielder, who has 201 caps for her national team, became the first women’s player to take part in seven Olympic Games after playing 72 minutes against China.
She made her Brazil debut at the 1995 World Cup as a 17-year-old and has played in every Olympic Games since women’s football made its debut at the 1996 Atlanta Games.
Having won silver at both the 2004 and 2008 Games, Formiga is looking to finally win that gold medal which has so far been elusive.
The 2016 Games, which were played on home soil, ended in heartbreak for Formiga and her teammates as they lost to Sweden on penalties in the semifinals before losing the bronze medal match to Canada.