Barcelona needed penalty kicks to see off Betis after an entertaining draw of more than 120 minutes at Riyadh’s King Fahd Stadium.
Robert Lewandowski put Barcelona ahead after 40 minutes, but Betis playmaker Nabil Fekir equalized with 13 minutes remaining.
Ansu Fati finished off with a fine volley to put Barcelona ahead in extra time, but Loren Morón dropped Betis with a deft heel strike.
Ter Stegen defeated Juanmi and William Carvalho in the penalty shootout and Pedri converted the decisive penalty.
Barcelona have not won the Spanish Super Cup since the switch to a four-team format, with the first edition in Saudi Arabia in 2020.
After finishing last season without a single trophy and investing heavily in the summer despite the club’s debts, Xavi and his team are desperate for trophies, and Sunday is their first chance to get them.
Pedri had an early shot disallowed for offside when the Catalans started well, but Betis soon found their comfort zone, inspired by the artistry of Fekir and the dynamism of Luiz Henrique.
However, Lewandowski, who missed the win over Atletico Madrid in La Liga on Sunday through suspension and was far from his prime, opened the scoring just before half-time.
The Polish striker’s first shot was blocked but he regained control of the ball and managed to beat Claudio Bravo at the near post.
Ter Stegen saved Rodri and Henrique to keep Barcelona ahead, in a hectic night for the German goalkeeper.
Fekir finally equalized in the 77th minute after clever footwork from Henrique, who assisted him, and the French midfielder past Ter Stegen at his near post to force extra time.
Three minutes into extra time, Fati worked magic to put Barcelona ahead again with a volley from the edge of the area.
It didn’t last long, with Betis pounding through Morón’s ingenious effort, backheeling past Ter Stegen despite Ronald Araujo’s attention.
Fati tried to respond with a heel, but the former Barcelona goalkeeper Bravo was alert to deny it.
Veteran Betis midfielder Andrés Guardardo was sent off at the end of extra time for two yellow cards, but Barcelona did not have enough time to capitalize before penalties.
Both teams converted their first two shots from the penalty spot but Ter Stegen plowed past Juanmi to give the Catalans the lead.
Fati scored and Ter Stegen produced another save to frustrate Carvalho, with Pedri converting the next shot from the penalty spot to seal Barcelona’s progress.