Real Sociedad 4-2 Real Madrid
Real Sociedad came back from two goals down to seal a famous victory over European champions Real Madrid.
The visitors, who were without the injured Cristiano Ronaldo, were superb in attack and led thanks to early goals from Sergio Ramos and Gareth Bale.
But Sociedad exposed their defensive deficiencies to level through Inigo Martinez and David Zurutuza.
Zurutuza struck again to give the home side the lead before Carlos Vela fired in to seal the victory.
Real Madrid coach Carlo Ancelotti has invested heavily this summer to further improve the attacking prowess of his side, with the big-money signings of Toni Kroos and James Rodriguez.
And the results of this were clear to see, particularly in the first half, as Madrid swept into a 2-0 lead.
Kroos' corner was converted by the head of Ramos after five minutes before Bale nutmegged his marker on the edge of the box and fired in to double the advantage six minutes later.
They could have had more with Marcelo twice going close and Ramos again showing his aerial prowess with a headed effort that just missed the target.
But as good as Ancelotti's side were at one end, they were poor at the other and were ruthlessly exposed by a clinical Sociedad side.
Martinez narrowed Real's advantage by tapping in at the back post after a corner had been flicked on by Xabi Prieto before Zurutuza capitalised on some more bad marking from the away side to power a header home from Alberto De la Bella's cross.
With the momentum behind them, Sociedad forced home their advantage in the second half as Madrid crumbled.
Zurutuza completed the turnaround by showing good determination to beat Dani Carvajal to a low cross from skipper Prieto and turn the ball in.
And Carlos Vela secured the victory by slamming a shot on the turn into the roof of the net.