Villarreal qualified for next season's Champions League with an entertaining 3-2 win at newly-crowned La Liga champions Barcelona on Sunday.
Elsewhere Kylian Mbappe struck as Real Madrid won 2-0 at nine-man Sevilla, while Leganes gave themselves a chance of survival with a win at Las Palmas, AFP said.
Barcelona stars celebrated their 28th league title on an open-top bus on Friday but Hansi Flick warned that "those who party, can work" and selected a strong side.
However the visitors took the lead through in-form striker Ayoze Perez, who slotted past Marc-Andre ter Stegen after Nicolas Pepe set him up.
Lamine Yamal, who scored a vital goal as Barca clinched the league on Thursday at Espanyol, scored another stunner to level.
The 17-year-old breezed past two defenders and arrowed a shot into the far bottom corner.
Yamal hit the bar before Fermin Lopez sent Barca ahead, walloping home from the edge of the box.
Santi Comesana lofted over Ter Stegen to equalize for the visitors, who nosed in front through Tajon Buchanan in the 80th minute.
Barca fell to their first home defeat of 2025 and also their first league reverse this year, but chants of "champions" rang around the Olympic stadium, on potentially the team's last game there before a return to the renovated Camp Nou next season.
The domestic treble winners were presented with the league trophy at the end of the game to cap a superb first season under Flick.
"We saw a lot of potential in the team... we can improve (Barca) a little a bit, they adapted to the idea of how we want to play and they showed they can play football," said a proud Flick.
"When you have confidence, everything is possible."
Villarreal booked their return to Europe's top competition as they opened up a big gap on Real Betis, sixth, as they were thrashed 4-1 at Atletico Madrid.
Julian Alvarez scored two and created another as Diego Simeone's side, third, ran out comfortable winners.
'Defend this shirt'
French superstar Mbappe netted his 29th league goal of the season to help Real Madrid to a narrow win over nine-man Sevilla in coach Carlo Ancelotti's penultimate match at the helm.
Loic Bade's 12th-minute red card for a professional foul on Mbappe set back the hosts, and then Isaac Romero was dismissed at the start of the second half for a high tackle on Aurelien Tchouameni.
Eventually the division's top scorer Mbappe drilled home Madrid's opener from distance and Jude Bellingham nabbed a second from close range late on.
"It was a strange atmosphere, at this club you always play for everything and today we weren't playing for much, but we have to defend this shirt," said Madrid midfielder Fede Valverde.
Madrid failed to win a major trophy this season after claiming a Champions League and La Liga double in the previous campaign, but will play in the Club World Cup this summer in the United States.
"We're excited and looking forward to it, proud to represent Madrid," added Valverde.
By the time Madrid arrive in the US they may have a new coach, with Bayer Leverkusen's Xabi Alonso poised to take over.
Veteran Luka Modric impressed for Madrid and is nearing the end of his contract, with the 39-year-old's future beyond the end of the season uncertain.
"Everyone knows how much Madrid loves Modric, they will have time to make the right decision," said Ancelotti.
"For the club, for him, and for the future."
At the bottom of the table Leganes took their fight for survival to the last day of the season with a 1-0 win at downed Las Palmas, thanks to Dani Raba's early strike.
The Madrid minnows, 18th, are two points from safety and face relegated Real Valladolid in their last game.
Espanyol's 2-0 defeat by Osasuna leaves them in danger of the drop and the Catalan side, 17th, welcome Las Palmas next weekend knowing a win would keep them up.
Getafe and Alaves secured safety with wins over Mallorca and Valladolid respectively.
