The attacking midfielder gifted the Amsterdam giants an early lead, before doubling his tally after the interval to help them to their second consecutive league title.Ajax won its 31st Eredivisie title after beating VVV 1-0 at the Amsterdam ArenA on Wednesday.
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 defense.
Ajax did get the early lead it was looking for 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 center 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 its lead. However, it took the club 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 own a six-point lead over second-placed Feyenoord with one more game to go. They lock horns with Vitesse on Sunday.
VVV is the Dutch top flight's No. 16 at the moment with 28 point from 33 games. It takes on Twente on Sunday before trying to save its Eredivisie status in the end-of-season playoffs against relegation.