The hosts couldn't get past Iraq in their second game of the competition, drawing 0-0 in a less than thrilling display.
This disgruntled young fan grabbed a marker pen and crossed out Neymar's name on the back of his replica shirt - replacing it with that of Marta, the women's team's iconic, talismanic striker.
The pictures quickly went viral on social media.
It's not the first time Brazil fans have drawn a comparison between the two footballing legends this summer. Chants of "Marta is better than Neymar!" filled the Olympic Stadium on the first day of competition as she laid on a brilliant assist for Andressa Alves to score against China en route to a 3-0 win.
Marta (BRA) of Brazil celebrates after scoring their fourth goal against Sweden
Image credit: Reuters
For her part, Marta has shrugged it off, sidestepping it as neatly as she sidesteps defenders on the pitch. When asked if it was fair to liken her to her male counterpart, she simply said, "Marta is Marta, Neymar is Neymar."
Neymar should be flattered to be likened to Marta. She's been named World Player of the Year five times - in five consecutive years - and she's the top goalscorer in Women's World Cup history.
No wonder the youngster picked her as his new favourite player.