MADRID: Robert Lewandowski left his mark with a pair of goals on his 34th birthday, and Barcelona saw its high-profile attack finally click in a 4-1 win at Real Sociedad for its first victory of the season on Sunday.Lewandowski also set up Ansu Fati’s goal as Barcelona quickly rebounded from a scoreless opening draw at home in the Spanish league against Rayo Vallecano in which the attack was ineffective.Ousmane Demb?l? also scored for the Catalan club that entered the season amid high expectations after spending big to boost its squad despite enduring financial difficulties.Lewandowski scored his first goal of the season a minute into the match with a nice touch from inside the area after a pass by teenager Alejandro Balde.The hosts equalized with a goal from Alexander Isak in the sixth minute after a nice through ball by veteran David Silva, but Barcelona’s forward stood out in the second half. Demb?l? scored with a low shot in the 66th after a backheel pass by Fati, who found the net himself in the 79th after Lewandowski’s assist. Lewandowski’s second goal came from close range in the 68th after another assist by Fati.The result kept Barcelona unbeaten against Sociedad in 13 league matches, with two draws and 11 victories.Sociedad had opened with a win at C?diz.