Stuart Pearce said Great Britain had been beaten by the favourites for Olympic gold after seeing his side outclassed by Brazil
The South Americans strolled to a comfortable 2-0 win in a one-sided warm-up match in front of a 25,000 crowd at Middlesbrough's Riverside Stadium.
First-half goals from Sandro and Neymar, the game's outstanding performer, underlined the gulf between the sides less than a week before the start of the Olympic football tournament.
Pearce's side, who are in the same group as the UAE, launch their campaign against Senegal at Manchester United's Old Trafford on July 26.
They were given a lesson by the visitors, and the coach admits the hosts are playing catch-up in their bid to produce a home success in the London Games.
"We knew how good Brazil would be," conceded Pearce, the former England international. "They're an outstanding side. We now understand the magnitude of the task ahead, because whoever beats Brazil will earn the gold medal.
"We know we need to come to the boil before next Thursday and beyond.
"Brazil have probably been preparing for the Olympics for the last two or three years. We've come through two games now and we're getting used to playing with each other.
"We've got five or six training sessions before the Senegal game. It's a steep learning curve."
It was a full directors' box as Premier League scouts flocked to see the visiting South Americans, rather than the crop of top young British talent, in a star-studded line-up largely expected to carry Brazilian hopes when they host the World Cup in two years' time.
Brazil coach Mano Menezes did his best to play down their chances of claiming gold in the Olympic final at Wembley Stadium on August 11, insisting: "It's too early to talk about medal candidates at this stage. Some teams are more prepared than others.
"It was a good work-out for us, but we're not worried about sending out messages to our rivals before the tournament. This was more about gelling together as a team."
After Sandro broke the deadlock early on with a looping close-range header, Neymar scored from the spot 10 minutes before the break after Manchester City's Micah Richards needlessly impeded Hulk.
Brazil have never won Olympic football gold but with Neymar, Chelsea-bound midfielder Oscar and Hulk all putting in eye-catching performances, their billing as pre-tournament favourites could not be denied.
Indeed, were it not for a fine display from Team GB substitute goalkeeper Jack Butland, the visitors' margin of victory would have been even more handsome.
In a rare bright spot for the hosts, Chelsea's Daniel Sturridge came through 45 minutes in his efforts to prove his fitness after being struck down by viral meningitis.
Pearce, who reported no fresh injury concerns, can call on a replacement up to the July 25 deadline.
He added: "We'll see how Daniel settles down overnight. The plan was to give him 45 minutes and we'll see how he is."
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