Victory continues Madrid's run of success under Zinedine Zidane with European champions now having lifted seven trophies in 20 months since Frenchman took charge.
Barca's Pique feels 'inferior' after Super Cup defeat to 'hungry' Real Madrid
Real Madrid shrugged off the absence of the suspended Cristiano Ronaldo to cruise past rivals Barcelona 2-0 in the second leg of the Spanish Super Cup to cap a 5-1 aggregate win.
Ronaldo was slapped with a five-game ban for pushing the referee after he was sent off in the first leg, but his replacement Marco Asensio enhanced his reputation as one of world football's rising stars as he smashed Madrid into the lead after just four minutes.
Karim Benzema then deservedly doubled Madrid's lead before half time.
Highlights from the game
Barca responded with a more spirited second-half showing and were unfortunate not to at least pull a goal back as Lionel Messi and Luis Suarez hit the woodwork.
Victory continues Madrid's run of success under Zinedine Zidane with the European champions now having lifted seven trophies in the 20 months since the Frenchman took charge.
"We played a great match tonight," Zidane said. "Especially in the first half it was spectacular."
Zidane even had the luxury of leaving first-team regulars Gareth Bale, Isco and Casemiro on the bench as Madrid's strength in depth was demonstrated in a dominant first 45 minutes.
"This team has hunger and every time we play it shows," Zidane added. "We have to try to continue like this. To start the season like this is very good, but we know a long season is just starting."
In similar fashion to his strike in the first leg, Asensio, 21, sent an unstoppable left-footed shot past Marc-Andre ter Stegen into the top corner from outside the box.
"I think we were superior across the whole tie," Asensio told Spanish TV station Telecinco.
However, he rejected suggestions he is now ahead of Bale in Zidane's pecking order.
"I am working to have as many minutes as possible on the field," he said. "I am happy on both a collective and individual level."
Super Cup final - in pictures
Barcelona manager Ernesto Valverde has suffered the worst possible start to his reign with back-to-back defeats against the Catalans fiercest rivals and the visitors never threatened to mount a comeback after conceding.
"We have to recover quickly, the league is on the horizon," said Valverde, ahead of Barca's Primera Liga opener against Real Betis on Sunday.
Shorn of Neymar after his world record-breaking transfer to Paris Saint-Germain and injured captain Andres Iniesta, Barca's star front two lacked the service needed to make a meaningful impact.
"In three days we find ourselves against the ropes," Valverde said. "Things have happened in pre-season that have affected the balance of the team and our job is to refind that balance."
Indeed, the scoreline could have been a lot more embarrassing for Barca as Marcelo dragged wide before Lucas Vazquez hit the post with a glorious chance.
The hosts finally doubled their lead six minutes before the break when Benzema nipped in front of Umtiti and slotted past Ter Stegen.
A late-night kick-off time meant half time saw on Wednesday turn to Thursday and Barca did at least salvage some pride in the early morning with an improved second-half display.
Madrid celebrate winning the trophy
Messi was desperately unlucky not to net a consolation goal as he hit the underside of the bar from a narrow angle.
The visitors' night was summed up when Suarez headed against the post with the goal gaping after Navas had parried Messi's driven shot into his path.
And there could be even worse news to come for Barca as Suarez ended the game visibly suffering from a knee injury that Valverde said will be assessed on Thursday.
Barcelona defender Gerard Pique conceded he felt "inferior" to Real Madrid for the first time after his side were humbled by their arch-rivals in the Supercopa de Espana.
It has been a humbling experience for Barcelona, who are now hoping to sign Philippe Coutinho and Ousmane Dembele and restore their swagger.
"This a long process and there is room for improvement, but in the nine years that I have been here, it is the first time that I feel inferior to Madrid," Pique said.
"We are not in the best moment, either as a team or as a club. We must stay as close as possible and keep moving forwards."