The South Africans slumped to their fourth consecutive defeat with Spain running out 1-0 victors last night.
Van Niekerk was, of course, supporting his sister Kayla Swarts, who was playing her second match of this Olympics for South Africa.
The more experienced Spaniards provided the South Africans with a lesson in how to be clinical in front of goal. South Africa had numerous chances, and controlled the possession and territory in the first quarter.
But it was the FIH Nations Cup champions that took the lead with their first clear shot on goal. Belen Iglesias tapped home after Spain forced a short corner as the first quarter ended 1-0 in favour of Spain.
The tide turned more towards Spain during the second half, and South Africa required a referral to rule out a second Spanish goal.
But still South Africa kept trying to find that equaliser and the impressive Kayla de Waal came closest, but her shot from the top of the circle was saved by Clara Perez.
Both teams started to tire in the searing Paris heat during the final quarter, which paved the way for opportunities at either end.
South Africa believed they had forced a penalty stroke after a scramble in the Spanish circle, but the decision did not go in favour of the girls in green as they had to settle for yet another defeat.
Giles Bonnet’s side will play their final Pool B match against the US tomorrow (1.15pm) and will hope for a consolation victory to take back home to South Africa.