Hope Powell's side emerged from the section as winners and they will therefore face Canada in the quarter-finals of the competition.
It was Stephanie Houghton who provided the decisive strike early on, making it two goals in three games for the 24-year-old defender.
Meanwhile, Brazil, who also advanced despite the loss, will face Japan in the next round.
With that in mind, Sports Mole dissects the 90 minutes of action between the two sides.
Team GB statistics:
On target 8
On target 8
Was the result fair?
A comprehensive yes. Powell's side started the match in the ascendancy, taking the lead after two minutes, while they staved off the Brazilian threat with solid defending. Brazil certainly had chances to level the match, but Team GB missed a decisive penalty.
Team GB's performance
Powell's side started extremely well, but they were guilty of fading as the opening half entered its latter stages. The expected onslaught from Brazil emerged in the second period, but gutsy defending from Houghton and Casey Stoney kept their clean sheet intact.
Full of class and imagination, but their so often perfect passing was just slightly off-target during the match. Marta failed to influence proceedings as she so often does, while Cristiane found it tough against the experience of Stoney.
Sports Mole's woman of the match
Stephanie Houghton: Woman of the match? Try woman of the tournament. It wasn't the fact that she opened the scoring, rather that her defensive work was simply excellent. She also attacked in equal measure in what could be considered the complete performance.
Carol Chenard got the big decisions right throughout the evening, however she was slightly lenient when Brazil started to become frustrated late in the second period.
Biggest gaffe of the game
This prize goes to Brazilian forward Cristiane. The striker has 12 Olympic goals to her name - a record - but she was guilty of missing a series of guilt-edged chances in the opening period.
Team GB: Next up for Team GB is a clash with Canada in the quarter-finals on Friday. A tricky one, but Powell would rather them than Japan.
Brazil: Following the defeat, Brazil must now face world champions Japan, whom they lost to the last time the pair met. It's the clash of the round.