Atletico Madrid cemented their second-placed standing in the Primera Liga on Sunday, while Malaga came unstuck on the road against a fellow top-four hopeful.
Elsewhere, Celta Vigo offered their survival bid a welcome shot in the arm and Real Valladolid claimed three points on their travels.
Atletico Madrid maintained their 100 per cent home record in the Primera Division this season by beating Espanyol thanks to a first-half Radamel Falcao penalty.
Diego Simeone's side had to play the whole of the second half with just 10 men after Gabi was sent off on the stroke of half-time, but their defence, which has now kept eight clean sheets in the row at the Vicente Calderon, was rarely troubled by a timid and impotent Espanyol.
Diego Costa, who was badly missed by Atletico in their two Europa League matches with Rubin Kazan, which ultimately saw them exit the competition, was a constant threat to the Catalans due to his pace and physical presence, and forced the penalty which lead to Atletico's opening goal.
He ran onto a pass by Falcao and was tripped by Hector Moreno. Again Atletico's players appealed for the Espanyol player to be sent off, but referee Carlos Clos Gomez produced just the yellow card.
Atletico made the most of the spot-kick though, Falcao sending Casilla the wrong way from 12 yards.
Real Betis got their European bid back on track in emphatic fashion after hitting high-flying Andalusian rivals Malaga with a first-half blitz at the Benito Villamarin stadium.
Jorge Molina opened the scoring inside the first 30 seconds and further goals from Mario and Dorlan Pabon increased Betis' lead before the interval.
The hosts even had the luxury of missing 35th-minute penalty through Molina as they comfortably picked up their first victory in six matches to climb back up to seventh spot on 39 points.
Shellshocked Malaga, who were beaten by Porto in the UEFA Champions League in midweek but had not lost in their previous five league outings, could find no way back after that first-half mauling and might have suffered an even heavier defeat after losing Nacho Camacho to a red card in the 63rd minute.
Manuel Pellegrini's side remain fourth in the table but are now just three points above Betis.
Rayo Vallecano's ambitions for Europa League qualification suffered a blow on Sunday as they were beaten 2-1 at home by Real Valladolid.
The visitors took a second-half lead thanks to an own goal by Jordi Amat, who then scored an outstanding goal at the other end to equalise.
However, Manucho fired Miroslav Djukic's side in front once more on 79 minutes.
New Celta Vigo coach Abel Resino enjoyed a perfect start to his spell in charge of the club with a hard-fought win over former club Granada.
Iago Aspas gave the home side the lead on 24 minutes and although that goal was soon cancelled out by Odion Ighalo, Mario Bermejo grabbed the winner nine minutes from the end.
Resino was named as Paco Herrera's successor on Monday and inherited a club in the relegation zone, four points from safety and without a win in their last six league games.
And although they remain in the bottom three, Sunday's three points means they are now just two behind Real Zaragoza in 17th.