Robert Lewandowski struck for Barcelona, who had defender Ronald Araujo sent off in the second half on a dismal night for the Spanish champions.
Rodrygo rounded off Real Madrid’s rout as they won the competition for the 13th time, avenging last year’s final defeat by record 14-time winners Barcelona.
Barca coach Xavi turned to a four-man midfield to try and keep the ball and reduce Madrid’s opportunities to counter-attack with flying wingers Vinicius and Rodrygo – it didn’t work.
Spain international Pedri started in place of winger Raphinha, who suffered a hamstring injury in the semifinal win over Osasuna.
Real boss Carlo Ancelotti brought in midfielder Toni Kroos, who like in the thrilling semifinal derby win over Atletico Madrid, was jeered by spectators at the Al-Awwal Park stadium in Riyadh, for criticising players moving to the Saudi league from Europe.
One of the first was Cristiano Ronaldo and Vinicius’ celebration brought him to mind after opening the scoring in the seventh minute.
The Brazilian, recently back after injury, was sent through by a perfect pass by Jude Bellingham and he slickly rounded Inaki Pena before slotting home.
Vinicius imitated Ronaldo’s classic jump and spin celebration in homage to Madrid’s all-time top goalscorer.
Three minutes later, Vinicius pounced again, this time set up by Rodrygo, who exploited Barcelona’s high line and cut the ball across for his compatriot to slide in.
Xavi’s side scrambled furiously for a response and Ferran Torres hit the crossbar before Andriy Lunin tipped Lewandowski’s follow-up over.
Lunin, selected over Kepa Arrizabalaga who let in three against Atletico, produced another solid stop to deny Torres from a tight angle.
The Ukrainian goalkeeper could do nothing, however, to keep Lewandowski’s vicious volley out in the 33rd minute, hammered in hard and low from the edge of the box.
Araujo swiftly gifted Vinicius a chance to complete his hattrick from the penalty spot by tugging back the forward in the box.
Vinicius drilled his penalty into the bottom-left corner for his first Clasico hattrick to double his goal tally against Barcelona – he had previously scored only three in 15 matches.
Xavi rolled the dice with a triple substitution, sending on attackers Joao Felix, Lamine Yamal, and Fermin Lopez, but Madrid soon had their fourth.
Araujo completed a dismal night by earning a red card as he crashed through the back of Vinicius for a second booking.
Rodrygo was in the right place at the right time to convert after Jules Kounde blocked a Vinicius cut-back searching for Bellingham.
Kounde cleared a low effort from England international Bellingham off the line as Madrid sought another goal to rub salt in their rivals’ wounds late on.