Here are five talking points from the weekend's action:
Striker Costa ends second spell at Atletico Madrid.
Simeone's side leapfrogged Real Sociedad into fourth on 42 points, while Sevilla stayed third in the standings on 46 after beating Las Palmas 1-0, also on Sunday, thanks to a late strike from substitute Joaquin Correa
Ronaldo had failed to score in his last four league games for Real and his rotten run in front of goal looked set to continue when his spot-kick was turned away by visiting goalkeeper Roberto.
Real Madrid crashed out of the King's Cup quarter-finals 4-3 on aggregate after being held to a 2-2 draw at Celta Vigo on Wednesday in another major setback for the stuttering European champions.
Karim Benzema scored twice after the interval with a penalty and a header from a corner to give Santiago Solari's side a 3-1 lead, after Raphael Varane struck in the 34th minute to cancel out Anuar Tuhami's goal for Valladolid five minutes earlier.
Morata, who had scored his first goal for the club in last week's 2-0 win over Villarreal, rose to head home from close range on the half-hour mark following a corner which had been flicked on by Atleti captain Diego Godin.
Costa turned Juanfran's low cross into the net in the 69th minute for Atletico's third goal in the first leg of the last 16 tie against third division Lleida but immediately limped to the sidelines. He did return to the pitch, however, and completed the game despite bleeding from his knee.
Real Madrid dropped points for the third time in seven games since Zinedine Zidane's return as they were held to a 0-0 draw away to Getafe in La Liga on Thursday, which harmed their neighbours' hopes of a top-four finish.
News of all that's transpired on and off the football field
Champions Barcelona came through a gruelling La Liga test at a rainswept San Mames on Sunday, beating Athletic Bilbao 1-0 thanks to Ivan Rakitic's first-half header.
Real Madrid produced a gutsy performance to earn a 1-0 win at Sevilla, on Sunday, which took them level on points at the top of La Liga
Underlying tensions mean Luis Enrique will not be remembered with the same reverence as Pep Guardiola, even though he has delivered a similar trophy haul.
Sergio Ramos made amends for his untimely own goal last week at Sevilla by scoring twice as Real Madrid bounced back from two successive defeats by beating Malaga 2-1 on Saturday to go four points clear at the top of La Liga.
Real Madrid ended their long wait for a La Liga victory by beating Real Valladolid 2-0 on Saturday with two late goals in interim coach Santiago Solari's first home game in charge of the struggling European champions.
Real Madrid became La Liga champions for the first time since 2012 on Sunday with a 2-0 win at Malaga, denying arch-rivals Barcelona three consecutive league titles.
Barcelona snapped a four-match winless run in La Liga with a 4-2 home victory over title rivals Sevilla on Saturday to reclaim top spot but the triumph was marred by talisman Lionel Messi fracturing his arm and being ruled out for three weeks.
IMAGES from La Liga matches played on Sunday
Football news from Ligue 1, Bundesliga and La liga.
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field
Luis Suarez was incredulous after being sent off in Barcelona's thrilling King's Cup semi-final second leg with Atletico Madrid on Tuesday, ruling him out of the final in May after playing a pivotal role in getting his team there.
Lionel Messi dragged Barcelona back from two goals down by scoring twice to snatch a 2-2 draw at home to Valencia in a thrilling encounter.
Germany midfielder Toni Kroos has eased Real Madrid's injury concerns and could be fit to play in their Champions League match at Borussia Dortmund on Tuesday, coach Zinedine Zidane said.
Lionel Messi was in inspired form as champions Barcelona hammered Celta Vigo 5-0 on Saturday, recording a fourth straight league victory which keeps them top of La Liga after Real Madrid had put the pressure on the Catalans with a 4-1 win at Eibar.
Presenting the best of Sanctuary Asia Wildlife Awards 2015.
Lionel Messi, Luis Suarez and Neymar combined to devastating effect as Barcelona swatted Celtic aside 7-0 at the Nou Camp to lay down a marker in Champions League Group C on Tuesday.
