JEDDAH, Saudi Arabia, Jan. 7 (Xinhua) -- Athletic Bilbao and FC Barcelona play the first semifinal of the Spanish Supercup in Jeddah on Wednesday, ahead of the second semi between Real Madrid and Mallorca on Thursday.

The match takes place under the shadow of Barca's failure to register Spain international Dani Olmo and forward Pau Victor for the second half of the season, after the club failed to meet financial fair-play regulations.

The pair have traveled with the rest of the squad to the Saudi Arabian city in the hope the club will be granted a last-minute reprieve and be allowed to register them, even though the rules clearly state a player can't be registered twice in the same season with the same club.

Barca coach Hansi Flick also has a doubt over the fitness of 17-year-old Lamine Yamal, who has been suffering from an ankle problem that saw him miss Barca's 4-0 win over fourth-tier Barbastro in the Copa del Rey last Saturday.

If Yamal isn't able to play, Pablo Torre or Ferran Lopez will accompany Robert Lewandowski in the Barca attack.

Athletic Bilbao qualifies for the Supercup as winner of last season's Copa del Rey, but had to work hard in the defense of its title as it was taken to a penalty shootout by UD Logrones.

Coach Ernesto Valverde will make plenty of changes to the side that made hard work of qualification on a dry and bumpy pitch in Logrono, with Nico and Inaki Williams both starting, and the team will be hoping to use their speed against Barca's high-pressure.

Nico was a transfer target for Barca last summer, and looking at Olmo's situation at the club, he must be thankful that he wasn't tempted to abandon Athletic, while Inaki was Athletic's hero last season as it knocked Barca out of the Copa del Rey, flying overnight to Bilbao after Ghana's exit from the Africa Cup of Nations to score the winning goal as his side won 4-2 in the quarterfinals. ■