European wrap: Barcelona go top of La Liga, AC Milan slump goes on
Barcelona returned to the top of the LaLiga table with a 4-0 rout of 10-man Real Sociedad.
Atletico had assumed pole position 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, who had Aritz Elustondo sent off in only the 17th minute for what was deemed a last-man foul on Dani Olmo.
Brilliant play from Lamine Yamal helped set up defender Gerard Martin for his first career goal in the 25th minute and - four minutes later - Marc Casado added the second.
Ronald Araujo then nodded in from five yards in the 56th minute before Robert Lewandowski completed the scoring on the hour mark.
Umar Sadiq's late goal earned lowly Valencia a point in an entertaining 3-3 draw with Osasuna.
Valencia twice led through Diego Lopez and Sadiq but were pegged back on both occasions by Aimar Oroz, and Ante Budimir's 45th-minute penalty looked to have earned Osasuna the win until Sadiq's 87th-minute intervention.
Mallorca slipped two points off the top six after they were held to a 1-1 draw by struggling Alaves.
Takuma Asano netted for the hosts in only the ninth minute but Kike Garcia equalised for Alaves midway through the second half.
Diego Garcia scored an injury-time winner to hand Leganes a much-needed 1-0 victory over Getafe.
Over in Italy, AC Milan's struggles continued as they fell to a last-gasp 2-1 home defeat against Lazio.
Sergio Conceicao's side sit in ninth place in the Serie A table after Milan goalkeeper Mike Maignan was deemed to have brought down Gustav Isaksen deep into stoppage time and Pedro converted the resulting penalty winner.
Mattia Zaccagni had put Champions League-chasing Lazio ahead in the 28th minute but Milan equalised six minutes