Real Sociedad thrashed Getafe 3-1 on Sunday afternoon at the Estadio Deportivo de La Coruna to maintain their lead at the top of La Liga.
The victory was Real Sociedad's fourth straight win and saw them extend their lead over second-placed Barcelona to four points with two games remaining in the campaign.
Isak, who has been in excellent form this season, was on target again as he scored his second goal for the club in just six days.
His double ensured that Real Sociedad moved up to fifth place in the league table, while Getafe remain in mid-table.
It was a tough game for Getafe, who were outplayed by their opponents throughout the match.
Real Sociedad started brightly and took the lead after just three minutes through a header from Vela.
They extended their lead further five minutes later when Isak curled home a powerful shot from outside the box.
Getafe hit back shortly afterwards through a well-worked team goal, but it was too little too late for them as Real Sociedad held on for a comfortable victory.
The result means that Real Sociedad will be looking to keep their momentum going as they face off against Sevilla next weekend.
Meanwhile, Getafe will need to regroup quickly if they want to avoid dropping further down the table.
Overall, it was another impressive display from Real Sociedad as they continue to show why they are one of the most feared teams in La Liga.