Gabriel Martinelli's 95th-minute winner saw Brazil dramatically come from behind to win 2-1 and advance to the World Cup last 16, cruelly denying Japan a first-ever knockout stage victory in the competition.
Carlo Ancelotti's side were staring down the barrel of a disastrous early exit when Kaishu Sano scored from the edge of the box in the first half - after he had breezed past Casemiro too easily.
But Casemiro made up for that slack defending by equalising after the break. Minutes after failing to convert a sitter, he headed home Gabriel's cross at the far post to the relief of the sizeable Brazil support in Houston.
Vinicius Jr almost turned the game on its head as his solo run and finish was palmed onto the post by Japan goalkeeper Zion Suzuki.
But Suzuki cruelly could not do enough with Martinelli's stoppage-time poke - only able to palm the effort onto the inside of the post before the ball rolled in.
Brazil advance to the round of 16 where they will play Ivory Coast or Erling Haaland's Norway. Japan, meanwhile, have led in each of their last three World Cup knockout games - and lost them all.
Brazil boss Carlo Ancelotti:
"This was the most complete game we have played [at the World Cup]. We had trouble in the first half as Japan were defending well, they were close and tight to us.
"In the second half, we overcame it, we got some space and put in crosses. This was an evolution [in tactics] for sure.
"At half-time I said ‌to the players to be patient, because sooner or later we would score a goal. But we had to keep our shape to ensure we did not compromise the ‌game further.
"Japan is a very good team, very organised, they create dangerous opportunities and get close (defensively). They are physical."
Your Site' Sam Blitz:
Brazil have the aura to get over the line in games like this. They have the options off the bench, even without Neymar, to crank up the pressure. They have the experienced trophy-winning manager to win the World Cup.
But they also have holes in their team. And that makes them beatable. They have to do better against the top sides if they are to go far.
Just like against Morocco, their midfield was massively exposed. Casemiro looked slow to the play, getting booked early on - which then played a part in his slack defending for Japan's goal.
Lucas Paqueta struggled to get in the game before coming off at half-time with injury. Endrick and match-winner Gabriel Martinelli contributed more.
Were it not for Bruno Guimaraes, who excelled at both ends of the pitch, Brazil would have had no midfield presence at all.
There is also a No 9 issue for Brazil. Matheus Cunha's quiet display proved - as Premier League fans have known all along - that he is not a No 9. Ancelotti has already trialled and scrapped the Igor Thiago experiment, while Cunha, Endrick and Martinelli all shared No 9 responsibilities against Japan.
Ancelotti still does not know his best Brazil XI. And that uncertainty spreads to the team. Brazil start games slowly - and better teams will put them away earlier.
Brazil cannot rely on Martinelli moments - they have to play better in the main.
