Promoted Numancia twice took the lead before falling 4-3 to champions Real Madrid at the Bernabeu in the Primera Liga on Sunday.
With a comfortable first-leg advantage, Zinedine Zidane rested much of his first team, making 10 changes from the line-up that struggled to a disappointing draw at Celta Vigo on Sunday to fall 16 points behind league leaders Barcelona.
Real Madrid are on the verge of reaching the King's Cup quarter-finals after winning 3-0 at Numancia on Thursday while holders Barcelona still have work to do after being held to a 1-1 draw at Celta Vigo.
David Villa made it eight goals from seven games with a brace in Valencia's 4-0 hammering of promoted Numancia.
Barcelona were held to a 1-1 draw at home by Racing Santander in the Primera Liga on Saturday, leaving new coach Pep Guardiola still seeking his first league win at the helm. Lionel Messi came off the bench in the second half to inspire a toothless Barca, who lost 1-0 at Numancia in their season opener, and scored a 71st minute penalty.
The Riazor jinx returned to haunt Real Madrid and the champions fell 2-1 away to Deportivo Coruna in their Spanish Primera Liga opener on Sunday, while Pep Guardiola's Barcelona were stunned 1-0 away to promoted Numancia. The performance of the day came from Atletico Madrid, who qualified for the Champions League group stage during the week, and stormed to the top of the standings with a 4-0 demolition of another newly promoted side Malaga.
The Brazilian striker had rushed back to his home country on Friday because of a family illness but said that the problem is now resolved.
Unzue is one of the two leading candidates to succeed Luis Enrique, who announced this month he will leave at the end of this season, along with Athletic Bilbao coach Ernesto Valverde.
La Liga champions Barcelona fell to their first opening day defeat of the season in 11 years when they were beaten 1-0 at Athletic Bilbao thanks to a sensational late overhead kick from veteran striker Aritz Aduriz.
News of all that's transpired on and off the football field
Morocco and Iran's hopes of making a mark at the World Cup before a ball has been kicked, and they head into their opening match in St Petersburg on Friday knowing defeat could likely mean an early exit.
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field