The holders and record 15-time champions will face either Real Madrid or Atletico Madrid, who meet Thursday, in Sunday's final.

Hansi Flick began with teenage star Lamine Yamal on the bench but his team was still able to ease to a comfortable victory at the King Abdullah Sports City stadium in Jeddah.

The La Liga leaders have now won nine matches in a row across all competitions and Athletic, enduring a difficult season, were ripped to shreds.

Last season Barca went on to win La Liga and the Copa del Rey after Flick's side won the Spanish Super Cup for the first trophy of the German's reign and the coach had said he wanted to use the competition as a springboard for more success again.

"It's us who make games easy or hard -- when we're playing well, doing things right, defending well, attacking well, the game is easier," Raphinha told Movistar.

The forward has been in fine form since returning from a hamstring injury that kept him out for around two months.

"I am always looking to be at my best level, and I will never say I'm at my best," continued Raphinha.

"I will keep looking, keep trying to have a season that, if not perfect, is almost perfect, always looking for the best for the team."

Ferran Torres bundled home the opener after 22 minutes with a stroke of fortune after Fermin Lopez's bungled shot fell kindly for him.

Barca sliced Athletic open with a more attractive second goal, with Raphinha cutting the ball back for Lopez to blast into the top corner, for the first of three goals in eight minutes.

Swedish winger Roony Bardghji got the third after being given a helping hand by Athletic goalkeeper Unai Simon, who somehow mishandled the low shot under his own body and into the net.

It offered Spain coach Luis de la Fuente food for thought, given Simon is his number one and Barca stopper Joan Garcia is knocking at the door ahead of the World Cup, although the Euro 2024 winning manager was absent with the flu.

Raphinha lashed into the top left corner for Barcelona's fourth after 38 minutes as the Catalans attacked relentlessly.

Oihan Sancet struck the post at the other end with Athletic's best chance on a miserable night for the Basque side, who last won the competition in 2021.

Brazil international Raphinha grabbed his second soon after the break with a lethal finish from close range to seal Barca's win.

"We have to say sorry to the fans who came here, we were not up to the level today, there's nothing else we can do than say sorry," said Athletic captain Inaki Williams.