Real Sociedad came from 2-0 behind to beat Real Madrid 4-2 at the Anoeta on Sunday evening.
Sergio Ramos and Gareth Bale had sent the away side into a comfortable two-goal lead early on.
However, strikes from Inigo Martinez and David Zurutuza left the scores level at the break.
Sociedad emerged stronger in the second period and added a third and then fourth through Zurutuza and Carlos Vela respectively.
Here, Sports Mole dissects the action between the two Spanish rivals.
Match statistics
Sociedad
Shots: 13
On target: 5
Possession: 45%
Corners: 8
Fouls: 18
Madrid
Shots: 19
On target: 5
Possession: 55%
Corners: 6
Fouls: 12
Was the result fair?
In truth, Madrid should have been out of sight in the opening 20 minutes or so, with Toni Kroos and Ramos both coming close to adding to their two-goal lead after 11 minutes. However, even after the missed chances, Madrid were still in an incredible position to go on and claim the three points.
Sociedad responded at a vital time, however, cutting the deficit after 35 minutes before levelling five minutes before the interval. Serious words would have been exchanged in the Madrid dressing room at half time, but it was Sociedad that emerged the stronger.
It wasn't as if the home team had to ride their luck in the second 45 minutes, with Los Blancos really struggling to carve out clear chances. Sociedad's third arrived after 65 minutes, leaving Madrid with plenty of time to respond, but Sociedad remained the team in control. Forgetting the opening 20 minutes, Sociedad were much the better outfit and deserved to claim all the points on their own patch.
Sociedad's performance
It was a surprise when the teamsheets were handed in and Vela and Sergio Canales were both on the bench. It proved a masterstroke from boss Jagoba Arrasate, however, with both influencing the match as the Madrid defence tired. It did appear that the home team would be on the end of a hiding after falling 2-0 behind inside 11 minutes.
As mentioned, it could and should have been more, with Madrid dominant enough to be leading by four or five goals. Sociedad had to ride their luck in the early moments, but there was nothing lucky about their comeback. You felt that they needed to score once before the interval, but they managed to find two goals, handing them the impetus in the second period.
Their defence tightened following a shaky opening, while the likes of Xabi Prieto and Esteban Granero proved strong influences in the middle of the park. They entered the match short of confidence after losing to Eibar last week, but they showed real character this evening. Not many teams will fall two goals behind against Madrid and still manage to win the match.
Madrid's performance
For the first 20 minutes or so, Madrid were sensational. Two goals, a number of opportunities and brilliant football in the final third. For some reason, however, that stopped as the half advanced. Sociedad continued to exploit the wide areas in the latter stages of the first period and they managed to capitalise on some poor Madrid defending.
Los Blancos were still in a strong position at the break, but entered the second half short of confidence and simply failed to match the tempo from the home team. There is no question that they missed the presence of Cristiano Ronaldo in attack, with Karim Benzema struggling for form and James Rodriguez still finding his feet. Their midfield went missing in the second half, meanwhile, with Kroos and Luka Modric overrun by a powerful Sociedad team.
Defensively the same old problems were present - individual errors and difficulty defending set pieces and high balls. Had a third goal arrived in the early stages, it might have been a different story, but the way the European champions threw it away will be extremely worrying for their supporters.
Sports Mole's man of the match
David Zurutuza: Zurutuza was simply the star of the show this evening. The Spaniard scored a crucial leveller in the latter stages of the first period, before moving Sociedad ahead after 65 minutes. While his brace helped him gain this award, it was not the sole reason. The midfielder was simply everywhere in the second period - making challenges in a defensive area before arriving in the box down the other end. It was just about the complete midfield performance.
Biggest gaffe
Just why Madrid boss Carlo Ancelotti failed to change his midfield in the second period is a question that only he can answer. It became almost immediately clear that Kroos and Modric were both struggling to deal with the threat from the home team, with Isco and James not really the type to track runners from a deep position.
Sami Khedira was the obvious change to provide a presence in the middle of the park in an attempt to stem the flow of pressure, but it took Ancelotti until the 74th minute to introduce the German international. Will Ancelotti be made to regret selling a certain Xabi Alonso?
Referee performance
Overall, it was a fairly routine night for referee Juan Martinez, who issued just the three yellow cards. Madrid were not happy with Martinez's decision to allow Sociedad's fourth, with Vela appearing to handle inside the box, but it would have been harsh on the Mexican. Aside from that moment, the match passed without major incident and the official was always prepared to let the play flow in the correct areas.
What next?
Sociedad: The Basque outfit travel to Celta Vigo in the league on September 13.
Madrid: Los Blancos welcome champions Atletico Madrid to the Bernabeu on September 13.