Barcelona lost an eight-goal thriller as Villarreal struck twice deep into stoppage time to leave Xavi's side 10 points off the top of La Liga.
The hosts had fought back with three goals in 11 minutes to lead after trailing 2-0 until the hour mark.
But Villarreal equalised with six minutes remaining and Alexander Sorloth put the visitors back in front in the ninth minute of stoppage time.
Jose Luis Morales then added a fifth after 102 minutes to seal victory.
Defeat leaves defending champions Barcelona third in the La Liga title race, 10 points behind leaders Real Madrid and eight points off Girona in second.
It comes after they were knocked out of the Copa del Rey quarter-finals in a 4-2 defeat by Athletic Bilbao on Wednesday.
It is Barcelona's third loss in five matches, with their other defeat in that run coming against Real Madrid in the Spanish Super Cup, which they lost 4-1.
After Gerard Moreno's first-half opener and Ilias Akhomach's 54th-minute goal, Barcelona produced a stunning comeback through Ilkay Gundogan, Pedri and an Eric Bailly own-goal.
But, following Goncarlo Guedes' 84th-minute equaliser for Villarreal, the hosts were left exposed in their pursuit of a late winner and ultimately punished by Sorloth's and Luis Morales' late goals.
Real Madrid came from behind to beat Las Palmas 2-1 on Saturday and moved back above Girona, who play struggling Celta Vigo on Sunday (13:00 GMT).
Latest Stories
-
Mahama likely to assent to E-Levy repeal bill on Wednesday – Deputy Finance Minister
4 hours -
Poland to suspend migrants’ right to apply for asylum
5 hours -
Zelensky hopes US will ‘stand strong’ in face of Russian demands
5 hours -
‘Only injury will stop me from being a part of the national team’ – Antoine Semenyo
5 hours -
UK-Ghana Chamber of Commerce launches the Grand Challenge Programme
5 hours -
E-levy was a massive error committed by Ofori-Atta, it was a bad policy – Dr. Ashigbey
6 hours -
LoveAid Foundation and partners empower women, girls in STEM
6 hours -
Heavy rainstorm caused power outages in parts of Accra – ECG
6 hours -
National Service Authority deploys 13,700 trained teachers for 2025/2026 National Service
6 hours -
Mahama urges CSOs to hold gov’t accountable
6 hours -
Daily Insight for CEOs: Enhancing financial resilience – Strategies for CEOs
6 hours -
Your dreams are too valuable to be sacrificed on drugs – Youth Minister
6 hours -
Thanks for inspiring us – Jordan Ayew pens emotional open letter to Ghanaians
6 hours -
GMet forecasts cloudy skies, thunderstorms on Thursday and Friday
7 hours -
Prof. Bokpin commends gov’t on tax policy reforms
7 hours