The Blaugrana came into the game on the back of a demoralising 2-1 defeat to arch-rivals Real Madrid in the La Liga. Meanwhile, Athletic Bilbao were without a win in five games coming into this one, so the odds were overwhelmingly in favour of Barcelona.
Barcelona manager Ronald Koeman had Gerard Pique making his first start in over a month, and the World Cup winner was slotted into the heart of a three-man defence.
Frenkie de Jong and Inaki Williams both went close for their respective teams inside the first 15 minutes, but that was as good as it got in terms of goalmouth action in a cagey first half.
The second half was anything but pragmatic, as an explosive start saw Barcelona fashion three good chances inside the first nine minutes, but Unai Simon was alert to keep the Blaugrana at bay.
Barcelona got the lead their bright start to the second half deserved when Antoine Griezmann scored with a deft first-time finish from Frenkie de Jong's square ball in the area on the hour mark.
They doubled their lead just three minutes later, and this time, it was De Jong who got on the end of Jordi Alba's cross with a low header inside the six-yard area.
Lionel Messi had struggled to make a mark on the game till that point. But the Rosario native got in on the act with what is a contender for the Puskas Award. The Barcelona captain received a pass from Oscar Mingueza 35 yards inside his own half.
He then proceeded to carry the ball for another 40 yards, dribbled across three Athletic Bilbao defenders and had a delicate one-two with Frenkie de Jong. After skipping across another two defenders in the box, he nonchalantly stroked the ball into the bottom corner, leaving Unai Simon stranded.
In many ways, it was a case of deja vu for the Basque outfit, as Messi had scored an almost identical goal in the 2015 Copa del Rey final against the same opponent.
The Argentina international was not done, though, and bagged his brace four minutes later when he scored a routine curler from the edge of the box. Jordi Alba was the provider of the goal with another pristine cross, and after a brief VAR check for a possible offside, the goal was allowed to stand.
There was still time for Barcelona to score one more, but Antoine Griezmann strayed marginally offside before beating Unai Simon, and the goal was rightly chalked off.
The victory saw the Blaugrana lift a record-extending 31st Copa del Rey title and their first trophy in any competition since the 2018-19 season.
On that note, let's take a look at five talking points from the fixture.
#1 Athletic Bilbao lose two Copa del Rey finals in the space of two weeks
Athletic Bilbao and Real Sociedad made it to the final of the Copa del Rey in 2020. But the emotional nature of the final saw both sides agree to defer it to a time when it would it be possible to allow fans to attend.
The two clubs are Basque rivals, and they were keen on playing out the spectacle in the presence of fans. That saw the unique scenario of the new season commencing without a defending champion in the Cup.
However, despite holding out for as long as possible, the rise in COVID-19 infections meant that it is still not possible for fans to be in attendance in matches in Spain.
That saw the two finalists play the 2019-20 Copa del Rey final at the start of April, where a second-half penalty by Mikel Oyarzabal saw Real Sociedad secure a 1-0 win over their city rivals.
Athletic Bilbao got a second chance to get their hands on the trophy just two weeks later. But a comprehensive performance by Barcelona saw Athletic Bilbao suffer heartbreak yet again.
#2 Copa triumph is an emphatic statement of intent from Barcelona manager Ronald Koeman
To state that the season started on a disastrous note for Barcelona would be an understatement. There was already speculation that Ronald Koeman would be sacked just a few months into the campaign.
However, the 58-year-old has since steadied the ship, which means the Blaugrana head into the home run of the season, still in the running for two trophies. That was hardly fathomable two months ago, so Koeman deserves praise for his tactical revolutions that have helped turn Barcelona's fortunes around.
The loss to Real Madrid last weekend was a spanner in the works, but the game against Athletic Bilbao offered Barcelona the chance to get back to winning ways. As it happened, they did so with a convincing performance that drew a throwback to the dominant displays of their golden era.
For all the strides Koeman has made in the Camp Nou dugout, managerial tenures at clubs like Barcelona are always measured by tangible success in terms of trophies.
Winning the Copa del Rey has put his name in the annals of successful Barcelona managers, and it has legitimised him in the eyes of fans. That could in turn, afford him more time to implement his vision at the club.