But the European side stuck by their high-line defensive tactic and were repeatedly ripped open as a result, with a slick Brazil attack creating chance after chance throughout an extraordinarily one-sided first half.
Richarlison struck again on 23 and 30 minutes to complete his hat-trick, but could have had five or six before the break such were the number of outstanding chances that fell his way.
And centre-forward Matheus Cunha was also guilty of a number of profligate misses from open play, as well as seeing his penalty saved by Florian Muller in first-half stoppage time.
Germany made some tactical changes for the second half and did get a goal back through Nadiem Amiri.
But Brazil were still comfortably the better of the two teams throughout the second 45, and that dominance only increased when Germany captain Maximilian Arnold received his marching orders for a second yellow midway through the half.
It felt for all the world like Brazil were coasting to a routine win, but Ache’s late goal gave Germany hope of rescuing the must unlikely of draws. But the equaliser never came and Brazil extended their advantage through Paulinho late on to secure the win they so heartily deserved.
Germany will need to improve dramatically if they are to reach the knockout stages, with Ivory Coast and Saudi Arabia the other two teams in Group D.
Brazil's forward Richarlison (R) celebrates with Brazil's forward Antony after opening the scoring during the Tokyo 2020 Olympic Games men's group D first round football match between Brazil and Germany
Image credit: Getty Images
Talking Point – Are Brazil favourites for gold now?
Spain went into the tournament with the strongest squad and the best claim to be favourites to win the gold medal match.
But Brazil’s sparkling performance means they must be considered one of the favourites for the competition now.
It wasn’t just the goals that struck a chord. It was the nature of the team’s build-up play and their aggressive work off the ball that really impressed, particularly in a dominant first-half.
Brazil are surely the team to beat.
Man of the Match - Richarlison
The Everton forward could have had so many more goals in a dominant individual display, but as it was he ran Germany’s defence absolutely ragged.
It feels like he’s been around for years, but the forward only just turned 24 in May, and is delivering on his potential.
Brazil XI: Santos 4; Alves 7, Nino 7, D Carlos 7, Arana 7; Guimaraes 8, Douglas Luiz 8; Antony 8, Claudinho 7; Cunha 7, Richarlison 9
8' GOAL! Brazil 1-0 Germany – It was coming and Richarlison opens the scoring for Brazil after being played in to the acres of space behind Germany's centre-backs. His first attempt was too close to the keeper, but the rebound came back out to the Everton man and he made no mistake with take two.
23' GOAL! Brazil 2-0 Germany – It's another for Richarlison, who is left unmarked in the box and times his run well to head home Arana's tempting cross. 2-0 and it should be more.
30' GOAL! Brazil 3-0 Germany – Another for Brazil! This is a rout and it’s a hat-trick for Richarlison. Cunha broke through the lines to launch a break, and he picked out a good a pass to set the Everton man up to cut inside on his right and curl a shot into the far bottom corner. 3-0.
45' PENALTY SAVED! Brazil 3-0 Germany – Muller produces a stunner of a save low down to his right to deny Cunha from the spot.
45' Brazil 3-0 Germany – Another huge chance goes begging for Brazil as Cunha skips clean through on an angle but skews his shot wide of the far post. That was an absolute golden chance and this could easily be six, seven nil for Brazil given the quality of their first-half chances.
57' GOAL! Brazil 3-1 Germany – Out of absolutely nowhere Germany have one back. It’s a decent volley from Amiri, but still should have been stopped by Santos, who made a real hash of the save.
62' RED CARD! Brazil 3-1 Germany – Germany captain Arnold is shown a second yellow and that glimmer of a chance didn't last long. It's damage limitation now.
83' GOAL! Brazil 3-2 Germany – Ten-man Germany are within one goal of securing the most unlikely of draws. Ache rises highest in the box to head home a teasing cross, and it's 3-2. Surely they can't do it, they've been ripped apart over and over again, but are just one goal from rescuing a result.
93' GOAL! Brazil 4-2 Germany – Game over. Germany were always going to be vulnerable as they threw numbers forward in search of an equaliser, and Paulinho finally makes it safe, cutting in on his right and dispatching an emphatic finish.
Richarlison’s hat-trick is the first scored by a Premier League player in Olympic Games history.