Barcelona is only the third team in the tournament's history to have won four successive tournaments on the trot.
Barcelona became the first team in 85 years to win four straight Copa del Rey titles after blowing away Sevilla 5-0 in the final on Saturday.
Luis Suarez scored twice and Lionel Messi, Andres Iniesta and Philippe Coutinho also made the scoresheet for Barcelona's record-extending 30th Copa triumph, and sixth in the last decade.
Sevilla was trying to win a sixth Copa and save a season which will end without any trophies and maybe not even a place in the Europa League next season.
The final took place at Atletico Madrid's Wanda Metropolitano Stadium in the capital amid the ongoing political turmoil involving Catalonia's bid for independence.
There were jeers by part of the Barcelona crowd when the national anthem was played, but the boos were largely subdued by the reaction of the numerous Sevilla fans in the crowd. Spain's King Felipe VI smiled and saluted the fans after the anthem.
Suarez opened the scoring with a shot into the open net after a breakaway that started with goalkeeper Jasper Cillessen in the 14th minute. Cillessen made a long pass from inside his area to Coutinho. The Brazilian playmaker entered the box free from markers before making a pass back to Suarez, who just tapped the ball in.
Messi scored with a mid-height shot from the middle of the area after a great backheel pass by Jordi Alba off the end line. Messi became the second player to score in five Copa del Rey finals, after Athletic Bilbao's Telmo Zarra.
Suarez scored again before halftime with a low shot after picking up a great throughball by Messi and fending off a defender while entering the area.
Fourth and fifth
Iniesta, who is likely to leave Barcelona at the end of the season, scored the fourth in the 52nd after a quick exchange of passes with Messi. He dribbled past goalkeeper David Soria and shot into an empty net.
Iniesta received a huge ovation by fans from both clubs when he was substituted near the end of the match. He then lifted the trophy, his sixth in the Copa.
Coutinho closed the scoring by converting a 69th-minute penalty kick after a handball by a Sevilla defender.
No other team had won four Copa titles in a row since Athletic Bilbao from 1930-33. The only other team to do it was Real Madrid from 1905-08.
Barcelona is also three points away from winning the Spanish league. Sevilla lies seventh, the final spot guaranteeing a Europa League berth next season.