Barcelona claimed their tenth straight Primera Liga win to narrow the gap to leaders Real Madrid to a single point with a 4-0 thrashing of Getafe.
Alexis Sanchez scored twice with further goals from Lionel Messi and Pedro as Pep Guardiola's men took advantage of their title rivals' surprise home draw with Valencia on Sunday.
Sanchez opened the scoring in the 13th minute following a through-ball by Messi, and the Argentinian made it on the scoresheet just before half-time. Sanchez's second in the 73rd minute was followed by Pedro's strike one minute later.
Two second half goals from Raul Garcia allowed Osasuna to recover from a nightmare week to beat nine-man Espanyol 2-0.
Osasuna had conceded 11 goals to Rayo Vallecano and Real Madrid in their previous two games, but had luck on their side throughout as Kalu Uche somehow blazed over from only five yards out early on.
Garcia then put the hosts in front eight minutes after the break as he volleyed in Lolo's cross, and Espanyol were reduced to ten men two minutes later when Philippe Coutinho was shown a second yellow card for kicking the ball away.
Garcia then added a brilliant second as he cleverly lobbed Kiko Casilla and the visitors' misery was complete with eight minutes remaining as Juan Forlin also picked up a second booking for a foul on Garcia.
Ruben Castro scored for the fourth time in five games to hand Real Betis a deserved 1-1 draw at Real Sociedad.
The hosts had the better of the opening period and were given the opportunity to take the lead five minutes before half-time when Jose Canas handled inside the area, but Fabricio made a fine save to deny Imanol Aggiretxe from the penalty spot.
Sociedad did eventually go in front thanks to another in-form striker, though, as Carlos Vela swept home Agirretxe's cross 11 minutes after the interval, but Castro applied the finishing touch to Jefferson Montero's fine run and pass 20 minutes from time to ensure the points were shared.