The result leaves Granada in fifth and means the leading seven teams are now covered by just three points, with Barcelona and Real Madrid still at the top.
Portu put Sociedad - who climb to third - ahead in the 21st minute and then scored an 89th-minute winner after Alvaro Vadillo had equalised for Granada in the first half.
Osasuna are up to ninth in the table after a 4-2 victory over Alaves that included three penalties.
A spell of three quickfire goals began in the 20th minute when Ruben Garcia opened the scoring for Osasuna.
Ezequiel Avila doubled the lead six minutes later but within a minute Victor Laguardia had pulled one back for Alaves.
Osasuna restored their two-goal advantage in the sixth minute of injury time at the end of the first half, Roberto Torres Morales converting from the spot after Ruben Duarte handled.
Alaves had their own penalty six minutes after the break following a foul by Nacho Vidal on Pere Pons.
Lucas Perez scored that one but remarkably there was a third penalty just four minutes later, this time Juan Villar netting for Osasuna after another handball, this time from Manu Garcia.
Kenedy's 37th-minute goal was enough for Getafe to beat Celta Vigo 1-0 and climb to the verge of the European places in seventh while Real Valladolid were convincing 3-0 winners over Mallorca.
Joaquin Fernandez opened the scoring in the 40th minute and the hosts doubled their advantage five minutes after half-time through a penalty from Enes Unal after he had been fouled by Fabri.
Sandro Ramirez added a third with the final kick of the game.
A tight game between European hopefuls Villarreal and Athletic Bilbao ended in a goalless draw.
There was another defeat for bottom side Leganes, who fell to a 2-1 loss at home to Eibar.
Leganes, with just one win all season, took the lead in the sixth minute through Youssef En-Nesyri but Charles equalised 11 minutes later.
It stayed that way until six minutes from time, when Kike netted the winner for Eibar.
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