Real Madrid's disjointed start to the season continued as David Zurutuza's double earned Real Sociedad a stunning 4-2 win in La Liga.
The European champions seemed set for a comfortable night on Sunday when early goals from Sergio Ramos and Gareth Bale left the home side shell-shocked.
But Sociedad regrouped outstandingly, with goals from Inigo Martinez and Carlos Vela complementing Zurutuza's brace to seal a famous triumph.
Questions have surrounded Carlo Ancelotti's Real side in 2014-15 so far after an uninspiring 2-0 win over Cordoba last Monday followed their Supercopa de Espana defeat to Atletico Madrid.
Those results supported claims that Real have lost their balance following the departures of Angel di Maria and Xabi Alonso, and a dreadful defensive showing on Sunday will only strengthen the arguments.
Initially, it did not seem those frailties would matter as Real, despite being without the rested Cristiano Ronaldo, attacked with menace and created chances at will.
But having found themselves 2-0 ahead after just 11 minutes, Ancelotti's men let Sociedad back into the game and were made to pay the heaviest of prices.
Real flew out of the blocks and took an early lead when Ramos rose to meet Toni Kroos' corner with a glancing header at the front post.
That set the tone for the rampant European champions, Ramos almost grabbing a second with a stunning free-kick that rattled the crossbar.
And Real did double their advantage in the 11th minute as Bale brilliantly nutmegged Gorka Elustondo and slotted a cool finish into the corner.
Not content with being 2-0 up, Real continued to press forward - only to see Marcelo twice spurn good chances before Ramos headed just over from a James Rodriguez set-piece.
The defender was pressed into action in his own box soon after, bravely flinging himself in front of Esteban Granero's powerful, goal-bound effort.
Normal service was resumed moments later as Enaut Zubikarai produced a fine stop with his leg to deny Toni Kroos.
The catalogue of missed chances looked costly in the 35th minute, Martinez sneaking in at the back post to convert after Xabi Prieto had flicked on a perfectly-placed corner.
And the scores were level six minutes later as Zurutuza arrived late into the box to powerfully head home Alberto de la Bella's centre.
Goals did not bring a defensive improvement for Sociedad, Ramos getting on the end of another free-kick and heading agonisingly wide.
Real's defending was not much better, illustrated at the start of the second half when an unmarked Imanol Agirretxe saw a header turned wide by the toe of Iker Casillas.
But the turnaround was complete in the 65th minute as Prieto and Sergio Canales played a one-two that ended when the former slid a lovely ball across for Zurutuza to slot home.
The verve with which Real attacked early on seemed a distant memory as they struggled for cutting edge.
Yet it was the issues at the other end that were most troubling, their inability to clear a set-piece proving costly when Vela followed a fine piece of chest control with a volley that arrowed into the top corner.
Sami Khedira, Rodriguez and Karim Benzema all missed golden opportunities thereafter as Real failed to find a route back into the game.
|Icardi: I would turn down Manchester United|
|Messi and Neymar inspiring Lukaku to silence the critics|
|Van Gaal impressed by ´excellent´ Giggs|
|Cannavaro sacked by Al-Nassr|
|Van Gaal proud of United work|
|Copa Libertadores Review: Independiente del Valle reach group stage|
|Mauro: Allegri should have Chelsea talks|
|Payet can become West Ham great - Sullivan|
|Rooney a target for Chinese clubs, says Eriksson|
|Klopp expects Liverpool´s Premier League drought to continue|
|Van Gaal: Woodward would tell me if he was speaking to Mourinho|
|Emery urges against Camp Nou final|
|Sagna: Man City still title favourites|
|Trelissac 0 Marseille 2: Fletcher opens account to seal quarter-final spot|
|Arsenal set for US pre-season fixtures|
|Lazio 5 Verona 2: Basement boys routed at Stadio Olimpico|
|Celta Vigo 2 Sevilla 2 (2-6 agg): Aspas brace in vain as Emery´s men reach final|
|Juventus v Napoli: Higuain confident he can handle pressure|
|Tan to write off Cardiff debts|
|Paris Saint-Germain v Lille: Champions seek to celebrate Blanc extension with win|
|Crystal Palace v Watford: Pardew hopes Adebayor can turn season around|
|Allardyce urges Van Gaal to discover Manchester United´s intentions|
|Sunderland terminate Johnson´s contract|
|Payet signs new West Ham contract|
|Oscar: I have no reason to leave Chelsea|
|Chelsea v Newcastle United: Oscar reflects on quest for form at Stamford Bridge|
|Pogba must improve mentality to become like Platini and Zidane - Mauro|
|AFC Bournemouth v Stoke City: Hughes praises Howe´s hard workers|
|Swansea City v Southampton: Koeman needs Wanyama to learn|
|Robinho returns to Brazil with Atletico Mineiro|
|Adidas terminates boot deal with Johnson|
|Sunderland consider Eboue deal|
|Sunderland v Manchester United: Carrick lauds Martial form ahead of key clash|
|Bundesliga record-breaker Nagelsmann replaces Stevens at Hoffenheim|
|Robben: No Manchester City move discussions with Guardiola|
|Borussia Dortmund v Hannover: Milosevic staying positive amid relegation fight|
|Norwich City v West Ham: Bilic eyes chance to build momentum|
|United poised for more heavy spending after record revenue|
|Pardew, Palace ´jealous´ of Leicester´s romantic title bid|
|Everton v West Brom: Martinez wants Goodison fortress|
|Allardyce confirms Johnson omission|
|Real Madrid not on Spalletti´s mind|
|Real Madrid v Athletic Bilbao: Valverde´s men out to improve shocking Bernabeu record|
|Angry Afobe hits back at Wolves after ´not trying´ accusations|
|Bojan agrees Stoke extension|
|Celina demanded international game-time - Norwegian FA|
|Manchester United profits surge after Champions League return|
|Prince Ali: FIFA is in crisis and needs to change|
|Aguero eyes further goal joy against Spurs|
|Deeney the perfect partner for Vardy and Kane with England, says Flores|
|Sirigu wanted PSG exit|
|Bordeaux suspend Prior and Sane|
|Saul in no rush to leave Atletico|
|Bilic: West Ham close to Payet deal|
|Martinez rubbishes Jagielka exit talk|
|Tomkins to miss five weeks with calf injury|
|Sunderland to drop Johnson for United match|
|Martinez: Title Leicester´s to lose|
|Xhaka tempted by Premier League switch|
|Carragher proud of Liverpool ticket-price U-turn|
|Mourinho and United a perfect match - McCarthy|
|Blanc extends PSG contract|
|Pulis heaps praise on Peterborough|
|Toranzo did not lose toes - Huracan president|
|Willian expects Terry to depart Chelsea|
|Mexico 2 Senegal 0: Duenas, Pizarro inspire win|
|Copa Libertadores Review: Sao Paulo, Racing qualify for group stages|
|Liverpool should be transparent with Sturridge injuries - Owen|
|FFA hands Wanderers fine and suspended points deduction|
|Luis Enrique: I had to give my voice a rest|
|Silva: I was not kicked off Marseille team bus|
|Blanc could sign PSG renewal by end of week|
|PSG drawn against familiar foes Saint-Etienne in Coupe de France|
|Neville confident Valencia fans will be back|
|Guardiola praises beaten Bochum|
|Coupe de France Review: Ibrahimovic sends PSG through, Nantes win thriller|
|I love penalties - West Brom´s shootout hero Foster|
|Ross County 0 Hearts 3: Dauda dazzles in valuable victory|
|Bayern Munich avoid Borussia Dortmund in DFB-Pokal semi-finals|
|FC Heidenheim 2 Hertha Berlin 3: Ibisevic at the double in DFB-Pokal|
|Hart: We will fight for Pellegrini all the way|
|Peterborough United 1 West Brom 1 (aet, 3-4 on pens): Foster spares Premier League team´s blushes|
|Paris Saint-Germain 3 Lyon 0: Ibrahimovic fires holders into last eight|
|Valencia 1 Barcelona 1 (1-8 agg): Kaptoum breaks record with late leveller|
|Bochum 0 Bayern Munich 3: Lewandowski double helps book semi-final spot|
|Colour clash forces Stoke to produce new kit|
|Hernandez to miss Darmstadt match with muscle injury|
|Stoichkov backs ´smart guy´ Neymar to stay at Barcelona|
|FSG´s letter of apology to Liverpool fans in full|
|Huracan bus overturns following Copa Libertadores clash|
|Liverpool scrap ticket price increases following fan backlash|
|Oviedo hopeful of new Everton contract|
|Zoff: Juventus-Napoli a Scudetto match|
|Bolton chairman Phil Gartside dies aged 63|
|Palermo turn to Bosi after Barros Schelotto exit|
|Ben Arfa considered retirement from football during exile|
|Bilic: We paid the price for cup progress|
|Griezmann happy to stay at Atletico|
|Wales to face Sweden in final Euro 2016 warm-up|
|Varela hopeful of long United career|
|Ki: I had ice on my face for two days|
|Niasse settling in well, could face West Brom - Martinez|
|Stevens leaves Hoffenheim on health grounds and retires|
|Diaby nearing return after near 18-month lay-off|
|Nasri would love to finish career at Manchester City|
|Captain Howedes extends Schalke stay|
|M´Vila keen to stay if Sunderland survive|
|Johnson admits child sex and grooming charges|
|Amazing Mahrez is one of Premier League´s best - Ulloa|
|Ronaldo, Messi rivalry good for football - Zidane|
|Barros Schelotto leaves Palermo|
|Age is just a number - Ilori defends Klopp´s team selection|
|Messi, Suarez and Neymar rested for Copa second leg|
|Madrid can dream of trophies under Zidane - Raul|
|Ancelotti: Italy job is a decade away|
|Reus will become a monster, says Dortmund boss Tuchel|
|Young Tottenham stars don´t know their limits - Lloris|
|Niang happy at Milan despite Leicester interest|
|Ticket price rise means more tourist fans, warns football supporters chairman|
|Ogbonna revels in first West Ham goal|
|Copa Libertadores Review: Huracan, River Plate advance to group stages|
|Klopp backs Benteke to rediscover goalscoring form|
|Turan will not leave Barca for China - agent|
|Beating Chelsea more difficult without Mourinho - Motta|
|Tuchel praises Dortmund for ´perfect game´|
|Klopp rues Liverpool wastefulness in FA Cup loss|
|Allegri: Chelsea rumours unfounded|
|Bilic feels weight of history after Liverpool win|
|Coupe de France Review: Second tier Sochaux stun Ligue 1 Monaco|