The turbo-charged stars roared to victory with two goals from Fred and a stunning strike from Neymar, dominating a weary Spanish side whose strength was sapped after edging Italy on penalties in Thursday's semi-final.
A miserable night for Spain also saw them miss a second half penalty when Sergio Ramos shot wide from the spot before Barcelona defender Gerard Pique was sent off for a professional foul on Neymar.
Brazil coach Luiz Felipe Scolari said the result as the perfect fillip as he plots a course to an assault on next year's World Cup finals in Brazil.
"People know a much tougher event is coming up (next year)," said Scolari.
But he noted: "We can set out on the journey with a little more confidence."
Spanish counterpart Vicente del Bosque meanwhile admitted his side had been outclassed on the night. "There are no excuses. Brazil were better than us. We must congratulate them," del Bosque said.
The touchpaper for an electrifying evening at one of the most iconic venues in football was set during the pre-match ceremonies as Brazil's fans in a 73,531-crowd belted out a spine-tingling rendition of the national anthem.
The stirring anthems came as police clashed with protestors outside the ground before kick-off, the latest in a series of violent confrontations which have dogged the tournament since it kicked off.
With the euphoric stadium crowd behind them, Brazil raced into a 1–0 lead after only two minutes through Fred's first of the night.
Hulk lifted over a cross and Neymar slid a hopeful ball to the centre forward, who was prone in the box as he flung out his right leg to hook home from point blank range past helpless Spanish custodian Iker Casillas.
Oscar then fired a low shot just wide after Fred played on a Neymar flick before a Paulinho chip almost embarrassed Casillas as Brazil poured forward, visibly boosted by the overwhelming din of support cascading down from stands.
Spain briefly responded with a swirling drive from Andres Iniesta which appeared to be drifting just wide before Brazil keeper Julio Cesar pushed the ball away for a 19th-minute corner which Fernando Torres.
Scolari, who led the Brazilians to their last World Cup success 11 years earlier to the day, had begun the event playing down expectations after the legendary Pele slammed the current side as not good enough to win top prizes.
But in recent days Scolari had suggested now was the time for next year's World Cup hosts to show they are back in business.
Rarely on a football field was a message delivered so emphatically as the hopes of the Spanish, struggling to impose their high tempo possession game, withered and died.
Spain central defender Pique, already booked for a first half challenge, was sent off for taking Neymar's legs under him after the break — the bearded star left the fray to chants of "Shakira," his Colombian partner.
Had Spain found some of the singer's rhythm they might have stood a chance — but such was the pace of the hosts' high-speed interplay they were down and
out after David Luiz made a superlative block in the 42nd minute.
Torres and Juan Mata produced an all-Chelsea interplay before sending Pedro away and the Barcelona forward arrowed an effort goalwards with Julio Cesar stranded.
As Brazilian hearts leapt into mouths, Luiz threw himself across the goal line to clear – prompting cheering that echoed back from the rafters.
There were niggly moments as Oscar, one of four Chelsea men on the pitch at the start, earned a booking for diving after a Ramos challenge.
Fred then saw Casillas make a fine stop with his legs from a low drive before the centre forward missed a free header.
But as the clock ticked down at the end of the first period Neymar made it 2–0, combining with Oscar before the Barcelona-bound starlet, just onside, twisted to smash an unstoppable left-footed drive past Casillas for his fourth goal of the event.
The 21-year-old vaulted the advertising hoardings to disappear in a sea of frenzied fans before embracing his teammates as the noise level climbed ever upwards.
Two minutes after the restart it was 3–0 as the swashbuckling Fred again showed why Scolari is such a fan, firing an unerring low drive wide of Casillas' outstretched arm after a brilliantly instinctive Neymar dummy.
Spain reacted as coach Vicente del Bosque, the only man to coach teams to the World Cup, the Euros and the Champions League, sent on Jesus Navas for Mata – but there would be no comeback for Spain.
After Marcelo fouled Navas there was still time for Ramos to send a spot kick wide for Spain as his effort summed up their evening — put on the spot, and found wanting, while Brazil showed that a sixth World Cup could just be there for the taking.