Vitoria, Spain: Real Madrid sank to a shock 1-0 defeat by Alaves on Saturday after a 95th-minute winner from Manu Garcia consigned the European champions to a fourth game without victory.
It is four games without a goal too for Julen Lopetegui's side, their longest scoring drought since 1985, as Garcia headed home to send the Mendizorrotza Stadium wild.
Alaves fans ran onto the pitch to celebrate their famous win and the chants continued long after the final whistle blew.
For Madrid this was another body blow and to make matters worse, Gareth Bale, their chief forward threat, had hobbled off injured late on. He missed the Champions League loss to CSKA Moscow on Tuesday with a groin strain.
Karim Benzema, out of form and bereft of confidence, was off too after being substituted at half-time but it was Thibaut Courtois at fault for the goal. He came for the cross but failed to claim.
It means Barcelona can go three points clear if they win their game in hand against Valencia on Sunday while Alaves' excellent start to the season continues. They move up to third, level on points with Real.
Lopetegui had been asked on Friday if he felt under pressure at the club he left Spain for on the eve of the World Cup. Talk of change is perhaps premature but it will certainly increase if Madrid cannot find fluency soon and, in particular, if Barca pull away.
The Clasico at the Camp Nou looms at the end of the month.
Bale had been passed fit to start while Luka Modric and Sergio Ramos returned after being rested against CSKA. Courtois took over from Keylor Navas in goal.
The first half was a fight, full of heavy touches, tussles and collisions but largely vacant of clear-cut chances.