Karim Benzema scored a brace as Real Madrid beat Athletic Bilbao 2-1 at San Mames to go top of the Primera Division on goal difference.

The Frenchman took advantage of an embarrassing error by Athletic defender Mikel San Jose to put Madrid ahead on 19 minutes and then restored their lead in the second half just three minutes after Sabin Merino had headed the Basques level.

This was by no means a vintage performance from Los Blancos, but thanks to Benzema's ruthlessness they picked up a fourth straight league win to go top of the league, ahead of Celta Vigo on goal difference. Rafa Benitez was still without Sergio Ramos, Danilo, James Rodriguez and Gareth Bale, but the coach handed a first start to Mateo Kovacic.

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Athletic had suffered a 3-1 defeat at Villarreal on the weekend but made a confident start against Madrid, whose defenders Raphael Varane and Dani Carvajal had to make precise tackles to prevent danger man Aritz Aduriz getting a shot away. But their plan unraveled when Iraizoz passed to San Jose from a goal kick and the defender hit a fatally soft back pass which Benzema hungrily pounced upon to score.

It took a while for the Basques to regain their composure but they managed to put pressure on Madrid again as the break approached, and Keylor Navas was forced to make a reaction save to keep out a close range header from Aduriz. Madrid broke quickly and astutely as Benzema cut the ball back to Kovacic, but Iraizoz stretched to deny the Croatian youngster.

Athletic were stronger in the second half as they plotted a way back into the game. Aduriz shot at goal from outside the area but Navas tipped the ball around the post. They eventually drew level thanks to a touch of fortune and the determination of Aymeric Laporte.

The French center-half drove forward from defense and lost the ball to Pepe but then won it back and switched the play out wide exquisitely and Merino came diving across the box to head the cross in off the far post. It was the first goal Madrid had conceded in 427 Primera Division minutes this season, but the euphoria in San Mames did not last long.

The left hand side of the hosts' defense dangerously was exposed and Isco gratefully raced into the free space and sent a low cross towards the back post for Benzema to tap in. Cristiano Ronaldo broke free on the left hand side but, faced with a difficult angle, failed to find the target and is still two goals away from equaling Raul as Madrid's all-time top scorer.

Athletic kept the pressure up after conceding until the end, but Navas again came to Madrid's rescue, twice keeping out powerful efforts from Aduriz to wait for Ronaldo's 500th career goal. The Frenchman opened the scoring on 19 minutes profiting from a bad mistake from Mikel San Jose who gave the ball away in his own area, allowing Benzema the simple job of slotting past Gorka Iraizoz.

Sabin Merino equalized for the hosts, heading home a great cross from Markel Suseata after 67 minutes, but three minutes later Benzema firing Real back in front from close range after good work from Isco.