Real Sociedad have gone to the top of the table after the sixth round of matches in the La Liga last weekend, thanks to a 3-0 win away to Betis.
The side from San Sebastian produced an excellent all-round display in a game between the teams who had started the weekend second and third in the table.
Sociedad opened the scoring on Sunday when Portu headed home Mikel Oyarzabal's cross two minutes before halftime.
Oyarzabal scored his team's second goal from the penalty spot in the 74th minute after Marc Bartra was penalised for pulling back Real Sociedad striker Alexander Isak. Adan Januzaj then rounded off an emphatic win with a thumping shot 14 minutes later.
After a 2-1 home victory over Valencia, Villarreal have climbed to the second place on goal difference.
Valencia sold midfielder Dani Parejo to join Villarreal in the summer to try and cut their wage bill but it worked out to be expensive when Parejo scored Villarreal's winning goal in the east coast derby.
Paco Alcacer's penalty put Villarreal ahead in the sixth minute. Although Goncalo Guedes' 37th minute thunderbolt levelled the score, Parejo's deflected shot in second half still gave the three points to Villarreal.
Cadiz produced the shock of the weekend on Saturday with a 16th minute goal from striker 'Choco' Lozano giving the recently promoted side their first ever away win against Real Madrid. Barca fared no better than Madrid as they lost 0-1 in Getafe.
Real Madrid now sit at the third spot while the Barca are at the ninth.