A partisan capacity crowd roared on Brazil in the Deodora stadium, where the hosts class told on a tough night for Barry Ferguson’s men.
The hosts opened the scoring with five minutes on the clock, Wanderson finding the bottom corner from a Diego Da Silva pass.
Wesley should really have made it 2-0 sixty seconds later when he rounded goal keeper Aaron Tier, Wesley however could only find the side net.
Gary Messett had Ireland’s only real half chance of the first half on 15 minutes, the visitors finally clearing their lines, Messett however blazed wide.
Leandro doubled the advantage two minutes later when his edge of the box shot deflected first off the head of captain Luke Evans and then off Carl McKee and past Tier, luck not shining on the Irish.
Diego made it 3-0 on 20 minutes after a sublime turn from Leandro which left the Irish defense flat footed, Diego finishing off the move at the back post.
Aaron Tier earned his corn a minute later with an expert point blank save as Leandro bared down on goal turning Luke Evans, Tier at full stretch on the ground.
Fabrizio headed home the games fourth goal four minutes after the restart with Leandro's pinpoint cross finding Fabrizio who heading across the goal and past Tier.
Brazilian keeper Marcos was then called into action, Luke Evans having cut down the right hand side and finding Dillion Sheridan whose scuffed shot was pushed away by Marcos.
At the other end Tier produced a fabulous foot block to keep Wesley’s shot out. Wanderson made it 5-0 on 41 minutes flicking Fabrizio’s edge of the box dive home, giving Tier no chance.
Leandro grabbed his second of the game on 49 minutes, Diego having turned O’Flaherty and pulling the ball across goal for Leandro to side foot home.
Dillion Sheridan grabbed Ireland’s first goal of Rio 2016 with 50 minutes on the clock. Sheridan held off the defender on the edge of the box and fired the ball across replacement keeper Gilvano into the bottom corner.
Brazil grabbed their seventh of the night three minutes later, Ireland caught out by the pacey Wanderson on the counter attack with Leandro grabbing his hat-trick sliding the ball under Tier.
The result means Ireland are unable to progress to the medal stage of Rio 2016 and will meet Great Britain in their final group game on Monday.
Great Britain lost 2-1 to Ukraine in the day’s other fixture in Group A.
Ireland: Tier, Markey, Evans, Messett, Birt, McKee, Nolan
Substitutes: McGillivary, Tuite, O’Flaherty, Walker, Sheridan, Tomiwa, Cotter
Brazil: Marcos, Jonatas, Fabrizio, Wesley, Diego, Wanderson, Leandro
Substitutes: Fernandes, Jose Carlos, Igor, Hudson Hyure, Gilvano, Maycon, Rafael
Referee: Skye Arthur-Banning (Canada)