Without taking into account La Liga, they have played 9 times in the last 10 years
The duel between Athletic Club Bilbao and FC Barcelona is becoming trendy. Without taking into account La Liga matches, two every season, both teams have faced each other 9 times in 10 years.
Taking into account that Athletic and FC Barcelona have never coincided in an European competition, these clashes have been in two competitions: 5 Copa del Rey matches and 4 Spanish Supercup games.
Copa del Rey matches
Curiously, until 2009 Barça and Athletic Club had only played 13 times in this competition. But after 2009 final, won by Barça for 4-1, a cycle with many duels began.
In 2010-11 season, they faced in Copa del Rey round of 16. The first leg, 0-0 at Camp Nou and the second, 1-1 in San Mamés, so Barça qualified. This has been the only match between them which didn't decide the title's winner.
The last two matches between them in La Copa have been the final: 3-0 Barça win in 2012 and 3-1 Barça win in 2015.
The other four matches between them have been in the Spanish Super Cup final. In all cases, FC Barcelona played as Liga and Copa winners and Athletic as Copa runner-up. In fact, these confrontations arose from the final played by Barça and Athletic Club.
Each team have won one of these two Super Cups. FC Barcelona won in the summer of 2009, 1-2 (first leg) and 3-0 (second leg.) This August, however, Athletic Bilbao won (4 to 0, with Aduriz hat trick) and tied in Barcelona (1 to 1), and won the Supercopa.