Rising striker, Neymar, 20, was the star of the show, turning in a fine individual display as Mano Menezes' men eased their way to victory.
Tottenham midfielder Sandro headed the visitors into a 12th-minute lead before Neymar converted a 35th-minute penalty after Micah Richards had tripped Porto frontman Hulk.
In truth, the Brazilians won with something to spare on a night when goalkeepers Jason Steele before the break and Jack Butland after it kept the scoreline respectable in front of a crowd of 24,721 at the Riverside Stadium.
Just what Team GB boss Stuart Pearce was able to glean from an intensely difficult evening is debatable, but his players were left in little doubt as to the standards they will have to reach if they are to figure at the business end of the Olympic tournament.
A bullish Pearce revealed in the build-up to the game that, rather than shying away from the tournament favourites, he welcomed the opportunity for his players to test themselves against the best before they begin their campaign against Senegal at Old Trafford next Thursday evening.
By the time the half-time whistle had sounded, he could have been forgiven for wishing he had taken a different route.
Team GB, who will play in the men's competition for the first time since 1960, were simply outclassed as the powerful South Americans went through their full repertoire.
Leandro Damiao was asked to lead the line ahead of a potentially lethal trio of Chelsea-bound Oscar, Santos starlet Neymar and Porto's Hulk, and they tormented Pearce's back four throughout the opening 45 minutes.
Left-back Neil Taylor in particular did not know what had hit him as, even with Tottenham midfielder Danny Rose trying to help him out, Neymar, who squandered a glorious sixth-minute opening, and Hulk repeatedly got in behind him to expose James Tomkins and Micah Richards in the middle.
Ironically, when the Brazilians did take the lead, they did so in somewhat prosaic style with Rose's Spurs team-mate Sandro heading Neymar's back-post free-kick across Middlesbrough keeper Jason Steele, playing on his home ground, and into the far corner.
GB might have been level within three minutes when Richards met Ryan Giggs' free-kick beyond the far post, but although his downward header beat keeper Rafael Barbosa, defender Thiago Silva was on hand to clear.
Chances were few and far between for Pearce's men, who started with Daniel Sturridge playing as a lone striker and attempting to prove his match fitness after a bout of viral meningitis.
But their task became even more difficult 10 minutes before the break when, after Richards had tripped Hulk inside the penalty area to leave French referee Clement Turpin little choice but to point to the spot, Neymar stepped up to fire the ball low to Steele's right and into the bottom corner.
The youngster had earlier angered the home fans before going to ground theatrically after attempting one too many step-overs as he tried to trick his way past right-back Ryan Bertrand, and his rapid recovery sweet strike did little to redeem him in their eyes.
He forced a solid 37th-minute save from Steele at his near post after once against escaping Taylor and saw a long-range effort deflected over the bar at the death with the hosts reeling.
Pearce made four changes at the break, but they made little immediate impact as the Brazilians started where they had left off.
Substitute keeper Butland, who went to Euro 2012 with England, was forced to save from Oscar and Damiao in quick succession with his defence offering little protection.
There was a glimmer of hope for Britain with 57 minutes gone when Rose did well to get forward down the left and produce an inviting cross for Bellamy, who was stunned to see Barbosa pull off a remarkable point-blank save, although an offside flag rendered his heroics unnecessary.
The half-time introduction of Scott Sinclair had given Team GB fresh impetus down the left, although the visitors were in cruise control as they eased towards the final whistle.
But had it not been for Butland, who clawed Neymar's 90th-minute shot out of his bottom corner one-handed and then palmed substitute Alexandre Pato's header over the bar, the margin of victory would have been even more comprehensive.