The attacking midfielder gifted the Amsterdam giants an early lead, before doubling his tally after the interval to help them to retain their domestic crownAjax have won the 31st Eredivisie title in their history after beating VVV 2-0 at the Amsterdam ArenA in Wednesday's encounter.
Siem de Jong gifted Ajax an early lead when he tapped home from close range after a dangerous cross from Ismail Aissati, before making it two after the break with a well-taken shot from inside the area.
The Godenzonen started the match with attacking intentions and came close to breaking the deadlock early on via Jan Vertonghen. Nevertheless, the Belgian defender's powerful shot only hit the upright, and was eventually cleared by the VVV defence.
Ajax did get the early lead they were after only minutes later, though. Aissati found De Jong with a superb cross from the right wing, and the forward eventually managed to push it over the goal-line after initially failing to beat the VVV goalkeeper with his header.
Again Vertonghen almost made it two with a well taken free kick, but the centre-back once more only hit the upright with his shot from 20 yards out.
The home side continued to dominate and created a number of chances to extend their lead. However, it took them until the 58th minute to score another goal. Aissati cut inside from the left before setting up De Jong, who made it two with a fine finish to put the match to bed.
The Amsterdam giants have collected 73 points from 33 games and have a six-point lead over second placed Feyenoord with one more game to go. They lock horns with Vitesse on Sunday.
VVV are the Dutch top flight's 16th-placed side at the moment with 28 point from 33 games. They take on Twente on Sunday before trying to save their Eredivisie status in the end-of-season play-offs against relegation.