Real Madrid were beaten 1-0 by Athletic Bilbao at San Mames on Saturday meaning if Barcelona beat Rayo Vallecano Sunday lunchtime they will move to the top of La Liga. Gareth Bale hit the post from 50 yards out but it was the closest Carlo Ancelotti’s team came as an Aritz Aduriz header in the first half was enough to give Athletic a famous victory that could seriously derail Real Madrid’s title charge. They started brightly enough with Karim Benzema swapping passes with Marcelo and crossing for Ronaldo, only for Xabier Etxieta’s clearance to stop the ball reaching Madrid’s top scorer. Aritz Aduriz (right) leads the celebrations with his Athletic Bilbao team-mates after putting them ahead with a tremendous header . The Bilbao players wheel away to celebrate with their supporters having taken the lead against Madrid . Karim Benzema (left) and Cristiano Ronaldo look on as the Bilbao team celebrate scoring in the first half . Carlo Ancelotti (right) saw his team dominate possession but struggle to break down Bilbao's defensive display . Aduriz (left) challenges Toni Kroos for possession in a stubborn defensive display from Bilbao at the San Memes . Athletic Bilbao: Iraizoz, Iraola, Balenziaga, Etxeita, Gurpegui, Benat, Mikel Rico (toquero, 91), De Marcos, Muniain (Susaeta, 64) Aduriz, Williams (Fernandez Hierro, 75). Subs not used: Aurtenetxe, Gomez, Remiro Gargallo, Lopez Cabrera . Bookings: Gurpegi, Etxeita, Aduriz . Goal: Aduriz, 26. Real Madrid: Casillas, Carvajal, Varane, Pepe, Marcelo, Illarramendi (Jese, 71), Isco, Kroos (Borges, 76), Ronaldo, Bale, Benzema (Hernandez, 80). Subs not used: Coentrao, Khedira, Navas, Nacho. Bookings: Marcelo, Illaremedi, Kroos, Isco. Att: 51,000 . Athletic had been on a good run with two league wins and a cup semi-final victory and they were soon into their stride with forwards Iñaki Williams and Aduriz stretching a Madrid defence under-protected by a midfield still missing Luka Modric who will not be back until midweek in the Champions League. When Athletic’s goal came it was that midfield weakness that created the opening. Mikel Rico had all the time and space he wanted to cross for Aduriz and the on-form centre-forward rose to head home his 18th goal of the season. Isco should have got across to Rico more quickly. Pepe might also be disappointed he was beaten so easily by Aduriz in the air, but the Athletic striker, who scored twice in midweek to put Athletic in the Cup Final, is on such good form that there is talk of a Spain call-up despite his 34 years. He hung for a moment in the air having got in front of the Real Madrid defender and powered his header past Iker Casillas. Real looked disjointed all over the pitch. Toni Kroos kicked-out at Andoni Iraola and was booked and Asier Illaramendi was yellow carded shortly afterwards for a foul on Iker Muniain. Athletic also had Aduriz and Etxeita booked but they were keeping their heads and their shape better than their rivals. Madrid raised the tempo in the second half and Bale lead the assault on Athletic’s goal. When he tricked his way down the right and pulled the ball back from the byline it looked like producing the equalizer. But before Ronaldo could sweep the ball home from three yards out Gorka Iraizoz got a hand to the cross to divert it to safety. Madrid's Marcelo (right) drops to his knees in response to chance being passed up by his team in the first half . Ronaldo cut a frustrated figure, especially in the first half, as his attacking threat was regularly nullified . Bilbao striker Inaki Williams (second left) tries to keep the ball away from the approaching Madrid player Asier Illaremendi . Marcelo (right) is crowded out by Bilbao players as the Brazil international tries to create an opening for Madrid . Isco forced a save from Iraizoz after taking a pass from Ronaldo but Athletic were keeping the European Champions at bay. Their keeper was making sure of it charging off his line to deny Benzema with Real’s next chance. Carlo Ancelotti took his time to make his first change and when it came it was a brave one. Winger Jese Rodriguez replace midfielder Illaramendi and Real went from 4-3-3 to 4-2-4 with Bale and Jese on the flanks and Ronaldo and Benzema through the middle. Ronaldo claimed a penalty when he tumbled over Iraizoz but the referee was right to call it Athletic’s way. Aduriz then went close with a header at the other end. Both Kroos and Williams were replaced by their respective managers with 15 minutes left. Williams had run himself into the ground; Kroos has been running himself into the ground for weeks and desperately needs to be rested. Despite the changes threir was still no way through for Real Madrid and Ancelotti played his last card replacing Benzema with Javier Hernandez. Bilbao defender Andoni Iraola (left) tries to control the ball under pressure from Madrid midfielder Kroos . Ronaldo (centre) vies for possession with Bilbao midfielder Mikel Rico in the La Liga encounter on Saturday . The impressive Bilbao striker Williams (left) holds off the challenge of Madrid defender Daniel Carvajal . Benzema (left) holds off the challenge of Benat Etxebarria in the La Liga match between Madrid and Bilbao . Ronaldo (left) queries a decision made by Spanish referee Alberto Undiano Mallenco during the defeat to Bilbao . With seven minutes left the leveler almost came in the most spectacular fashion. Tired of Real’s attempts to pass through the defence, Bale lifted his head just inside of Athletic's half and tried to lob Iraizoz. The audacious long-distance shot came back off the frame of the goal. Even by his high standards it would have been a spectacular goal. It also would have been very hard on Athletic who deserved their three points .
Aritz Aduriz put Athletic Bilbao into a shock lead in the 26th minute with a powerful header . Gareth Bale smacked the post with an astonishing attempt from around 45 yards out for Real Madrid on 83 minutes . Barcelona have the chance to replace Madrid in first place on Sunday after the defeat .