The Spanish and European champions were dominant, even without the suspended Cristiano Ronaldo.
Marco Asensio, who also scored in the 3-1 first-leg win, gave them an early lead with an excellent 25-yard strike.
And Karim Benzema flicked up Marcelo’s cross and turned defender Samuel Umtiti to fire home a second with Barcelona rarely looking like coming back.
Real eased off in the second half, with the cup practically wrapped up, and Barca improved slightly as a result, with Lionel Messi and Luis Suarez hitting the woodwork.
In less than two years in charge, Zinedine Zidane has led Real to two Champions Leagues, and the 2016-17 La Liga title. And on this performance, they are going to be hard to beat again.
The big story before the game was Ronaldo claiming he was persecuted after being banned for five games – for pushing the referee – after being sent off in the first leg.
Watching from the stands, he was not missed on the pitch, with Zidane also able to leave Isco and Gareth Bale on the bench with Sunday’s La Liga opener against Valencia in mind.
But in 21-year-old attacking midfielder Asensio, they have one of Europe’s most talented youngsters, and four minutes in, he fired home an excellent shot that left Marc-Andre ter Stegen rooted to the spot.
Benzema added a second with a great two-touch goal, and Real could slow things down after the break, knowing Barcelona did not look capable of scoring four unanswered goals.Follow Us On All Social Platforms.