Luis Suarez opened the scoring on a memorable evening for Ernesto Valverde's charges when the Uruguay forward collected from Philippe Coutinho to slot a simple finish past a stranded David Soria in the Sevilla goal after just 14 minutes.
Andres Iniesta might have made it 2-0 to the Catalan side not too long after, but the Spain midfielder saw his effort cannon back off the crossbar after initially being teed up by Suarez.
Barcelona moved into a comfortable position in the 31st minute when Lionel Messi became the second player to ever score in five Copa del Rey finals. The Argentine profited from a wonderful one-two between Jordi Alba and Iniesta to hammer a finish into the roof of the net.
Valverde's charges rounded off an impressive first half when Suarez returned to bag a brace before the interval, the forward partnering with Messi before slotting a cool finish beyond Soria to round off an attacking move of the highest quality.
Barca's dominance continued after the break and they found a fourth through Iniesta, who received a perfectly-weighted ball from Messi before rounding Soria and tapping home in what could be his last final appearance for the club.
Philippe Coutinho cemented a standout night for the soon-to-be La Liga champions, the former Liverpool midfielder lashing home from the penalty spot in the 69th minute, after Clement Lenglet was penalised for a handball when intercepting a flick from Suarez.
