Both teams oozed confidence in the opening salvos, but it was Japan gloveman Zion Suzuki who was called to task first. The goalkeeper tipped Matheus Cunha's strike around the post as Brazil pressed.
The Samurai Blue opened up the scoring in the 29th minute. Midfielder Kaishu Sano intercepted the ball on the halfway line and snaked his way past a couple of defenders to unleash a magnificent effort from the edge of the box into the bottom left corner, giving stopper Alisson Becker no chance.
In the second stanza, Brazil pushed hard for the equaliser. First, Suzuki pulled off another fantastic save to deny a header from Bruno Guimaraes. Then two minutes later, Japanese defenders combined to thwart Casemiro's diving header from just a few metres out.
But Casemiro had another chance, and this time he made it count. The Brazilian legend rose above the rest and headed home from close range after a brilliant cross evaded the keeper.
Just two minutes later, Suzuki kept Japan in the game with yet another superlative reflex save to deny mega star Vinicius Junior's stab at goal.
Japan continued to fight, living solely off scraps from the relentless Brazilian attack. The game moved ever closer to extra time, but the five-time World Champions were not going to be denied.
Bruno Guimaraes was in space in the box, but he saw his teammate Gabriel Martinelli in a better position. Martinelli had a perfect first touch before finally beating Suzuki with a precise shot that bounced in off the bottom of the right post, cuing the death knell for a crestfallen Japan.