Hapless Real Madrid suffered an extraordinary 4-1 defeat away to Sevilla, while Valencia went down 2-1 at home to Racing Santander to leave Deportivo Coruna top of the table in Spain on Sunday.
Real, needing a win to reclaim the league leadership from Deportivo, found themselves 3-0 down inside 15 minutes against Sevilla with an Ivan Helguera own goal and excellent strikes from Dario Silva and Daniel Alves.
Javi Casquero crashed in a fourth eight minutes before halftime to leave the reigning league champions reeling.
Ronaldo pulled one back with a drilled shot 10
Real's defeat followed a less dramatic setback for Valencia, who went down 2-1 as Rodolfo Bodipo struck twice for Racing.
Those results gave Deportivo Coruna full value for their 2-1 win at home to Real Sociedad on Saturday, taking the Galicians top of the table with 25 points from 11 matches.
Valencia slipped to second on 23, with Real staying behind them in third on goal difference.