[16] In the 1910 Copa del Rey (which had two rival tournaments running in parallel), the two clubs participated in the three-team group of the UECF competition along with Madrid FC.

The decisive match was between the Basque teams (Athletic winning 1–0),[17][18] but as it was not a final in the traditional knockout format and the newly-formed Real Sociedad were playing under the name 'Vasconia' for licensing reasons,[19] it was not widely recognised as an equivalent to their meeting 110 years later.

However, on 30 April, UEFA stated that the final must be played by 3 August to activate the designated qualification place, otherwise this would revert to the team finishing seventh in La Liga (either with the fixtures completed or the standings declared).

Athletic submitted a formal protest against UEFA's instruction,[23] and on 4 May both teams officially reiterated their stance to delay the match until such a time as supporters would be able to attend it.

[24][25] When the league resumed in June 2020, the form of both clubs was poor: Athletic Bilbao collected 14 points from 33 available, while Real Sociedad gained only 10 points and slipped down the table; however, five of those came in the last three matchdays, including one from an 88th-minute equaliser against Atlético Madrid on the final day[26] to keep them just above Granada and Getafe – they finished sixth and qualified for the Europa League group stage, the same status as would have been afforded the Copa winner.