Rival players and coaching staff embraced in the centre of the pitch as the Santander fans chanted support for the home team's actions.
The Santander players announced on Monday they would boycott the match unless club president Angel Lavin and the board of the cash-strapped third tier side resigned.
Santander lost last week's first leg 3-1 at the Anoeta stadium in San Sebastian and their chances of making the last four and setting up a meeting with record King's Cup winners Barcelona were remote.
(Reporting by Iain Rogers; editing by Tony Jimenez)