Luis Suarez's double punished a wasteful Real Madrid as Barcelona won 3-0 at the Bernabeu to reach the Copa del Rey final 4-1 on aggregate.
With Gareth Bale watching on from the bench, Vinicius Jr and Karim Benzema were both guilty of missing first-half opportunities in what was the first of two Clasicos in the space of four days.
Suarez then scored with Barca's first shot on target after the break (50) and netted his second with a Panenka penalty (72) just three minutes after Raphael Varane turned the ball into his own net.
The victory sees Barcelona reach a sixth straight Copa del Rey final, and Ernesto Valverde's side will face the winners from Thursday's other semi between Valencia and Real Betis, which is finely poised at 2-2.
Real dominated the first half but missed numerous opportunities to break the deadlock, with 18-year-old Vinicius spurning four chances.
The winger fired over from 15 yards out before being denied from point-blank range by a sprawling Marc-Andre ter Stegen.
A last-ditch block from Jordi Alba then thwarted the Brazilian, and after Karim Benzema saw his follow-up attempt saved, Vinicius sent another attempt over when unmarked eight yards out.
Barca failed to record a shot on target in the opening 45 minutes, but after the break they immediately punished Real, with Suarez coolly slotting in at the near post from Ousmane Dembele's cut back.
Ter Stegen then preserved Barca's lead with a flying save, parrying away Sergio Reguilon's header which appeared destined to find the far corner.
It then quickly unravelled for Real, with Varane inadvertently sending the ball into this own net from Dembele's cross, before Suarez picked himself up following a Casemiro foul to dink in the boldest of penalties.
Man of the match - Luis Suarez
The Uruguay forward looked a forlorn figure in the first half, and was sat down inside the tunnel moments before the second half seemingly deep in thought after a difficult 45 minutes.
But after the break he delivered Real a lesson in finishing, superbly letting the ball roll across onto his right foot for the first goal, even with Sergio Ramos in close proximity.
Then, the penalty. No one loves a Panenka more than Ramos, but the Real captain could only watch on as Suarez dared and succeeded with the most audacious of spot-kicks on enemy territory.
What's next?
Another Clasico encounter at the Bernabeu, this time in La Liga. Barcelona are currently seven points clear at the top of the table with 13 games to go. Real are third, two points behind Atletico Madrid.