There are teams that beat the La Liga giants FC Barcelona and Real Madrid once or twice in a couple of seasons. Then there is Athletic Club, commonly known as Athletic Bilbao or just Athletic, who beat them and knocked out both teams from the Copa Del Rey this season. First, they knocked out Barcelona in the Round of 16 and then in the quarter-final, they fought hard to beat Real Madrid for a single goal. Alex Berenguer scored a superb 89th-minute winner. 

After Real Zaragoza, they became just the second side to knock Real Madrid and Barcelona out of the cup in one season.

Athletic last won the trophy in 1984 and lost the 2020 and 2021 finals to Real Sociedad and Barcelona, respectively. The Basque side completes an incredible semi-final line-up alongside Real Betis, Valencia and Rayo Vallecano. 

Athletic are the fourth most successful club in La Liga with eight titles to their name. In the Copa del Rey titles table, Athletic is second only to Barcelona, having won it 23 times. They are also the most successful Basque football club in both league and cup titles won. The club also has one of the most successful women’s teams in Spain, which has won five championships in the Primera Division Femenina.

The club is one of three founding members of the Primera Division that have never been relegated from the top division since its inception in 1929. The others are Real Madrid and Barcelona. 

The club had been performing consistently in the last couple of years. 

The beginning of the 2019–20 season saw more consistent results. After the first five games of the season, the Lions sat at the top of the table, their best start in 26 years. That form could not be maintained, and by the halfway point, they had slipped to mid-table after several draws. However, in the Copa del Rey, they survived two penalty shootouts against second-tier opponents and then defeated Barcelona to reach the semi-finals.

The club then defeated Granada CF in the semi-final on away goals to meet local rivals Real Sociedad in the final, which was then postponed due to the COVID-19 pandemic in Spain. Both clubs were happy to delay in the hope of supporters being able to attend the historic Basque derby occasion. This did not come to pass, and the final was eventually played in an empty stadium on 3 April 2021, Real Sociedad emerging winners by a 1–0 scoreline.

By that time, Aduriz had finally retired from playing, Garitano had been replaced as coach by Marcelino, and the 2020–21 Supercopa de Espana originally intended to follow the delayed cup final was contested Athletic defeating Real Madrid then Barcelona to claim the trophy.

They also defeated Levante in the semi-final of the 2020–21 Copa del Rey to reach the final on 17 April 2021, making them the only team to participate in the showpiece event twice in as many weeks.

However, Athletic lost that final as well, to Barcelona by a 4–0 scoreline.

In October 2021, the International Centre for Sports Studies (CIES) report showed that Athletic Bilbao and Desna Chernihiv (Ukraine) were the only teams in continental European competitions without foreign players.