London (PA Media/dpa)
Barcelona returned to the top of LaLiga with a 4-0 rout of 10-man Real Sociedad on Sunday.
Atletico had assumed top spot on Saturday after city rivals Real Madrid suffered a shock defeat at Real Betis. But Barca had no such issues at home to their mid-table opponents, once they had Aritz Elustondo sent off in only the 17th minute.
There was an element of contention about the dismissal after Robert Lewandowski's clip over the top had sent Dani Olmo off on a foot race with the Sociedad defender.
The pair tangled 15 yards inside the visitors' half and the Barcelona midfielder tumbled to floor, prompting referee Alejandro Quintero to immediately brandish the red card, despite the apparent proximity of Javi Lopez.
That made the task even more daunting for Sociedad, who since 1995 have lost on every league visit to Barcelona bar one, and they buckled under the pressure, twice conceding two goals in five minutes in either half.
Defender Gerard Martin may have scored his first career goal for the opener but the real genius was provided by 17-year-old star Lamine Yamal.
Collecting the ball out on the right, the teenager beat his two markers, with the chop back onto his left foot close to the byline and leaving Lopez on his backside.
That opened up the space for him to roll a pass inside to Olmo, who cleverly spotted Martin running in at the far post and scooped a cross for the left-back to volley home.
A 25th-minute Raphinha corner was cleared only to the edge of the penalty area where Olmo was lurking.
He fired back the shot which Marc Casado, half trying to get out of the way, half trying to turn his body to into a position to control the ball, managed to deflect past Alex Remiro from the penalty spot.
Pedri and Olmo were both denied by Remiro before half-time but Sociedad's resistance did not last much into the second half before Barca struck twice in quick succession again.
Lewandowski's flicked near-post header was kept out by the goalkeeper's left foot on the line but the ball bounced up kindly for Ronald Araujo to nod in from five yards in the 56th minute. The centre-back then inadvertently turned provider as he took aim from 28 yards.
With Remiro committed to the dive to his right, Lewandowski's cute touch with the outside of his right boot inside the penalty area gave the goalkeeper no chance.