VAR will be used from this stage onwards, and all matches are hosted by the lower-ranked team.
Los Blancos have been paired with Albacete, who earned their last-16 spot by defeating Leganes. Real Madrid progressed after a nervy 3-2 win over CF Talavera in December, with the minnows making the game a tense affair. The match will take place at Albacete's Estadio Carlos Belmonte.
Defending Copa del Rey champions Barcelona will visit Estadio El Sardinero to face Racing Santander, a team that caused a major upset in the previous round by eliminating Villarreal. Juan Carlos Arana scored twice for Racing, while Barcelona booked their place with a 2-0 victory over CD Guadalajara, thanks to goals from Andreas Christensen and Marcus Rashford.
Among the remaining Segunda sides, Rayo Vallecano recently overturned a first-half deficit to beat Granada 3-1 in a postponed fixture. Goals from Alvaro Garcia, Pedro Diaz, and an own goal from Flores Flores secured the win after Pablo Saenz had opened the scoring.
The four Spanish Super Cup participants - Real Madrid, Barcelona, Atletico Madrid, and Athletic Club - are seeded in this round and cannot face each other until the quarter-finals. All Round of 16 matches are single-leg fixtures, with home advantage going to the lower-ranked team unless both sides are in the same division. Quarter-finals, set for the first week of February, will see seedings removed, potentially opening the door to high-profile clashes.
With Spain's elite clubs facing ambitious underdogs, the Copa del Rey is set for a thrilling knockout phase.