Mired in the relegation zone in La Liga, Villarreal were held to a 1-1 draw by third-tier outfit Puertollano in the pair's Copa del Rey fourth-round first leg on Thursday 29 October.
Alvaro Valdes put the hosts in front after 13 minutes and Villarreal replied 22 minutes from time through the evergreen Robert Pires, who was celebrating his 36th birthday.
Meanwhile, Racing Santander must overcome a first-leg deficit after falling to a 1-0 loss at Salamanca, the home side grabbing a narrow win via Salva Sevilla's 87th-minute penalty.
Real Valladolid beat Mallorca 2-1 in the night's other Copa clash. Cesar Arzo and Diego Costa were on target for Valladolid, with the visitors' reply coming from a penalty by former Sevilla midfielder Jose Luis Marti.
