The 17-year-old was taking part in a race on Sunday when the Red Hartebeest buck, charged across the plain right into him.
There was little the biker could do to stop the the large antelope crashing into him, knocking him from his bike.
The animal stumbled to its feet and ran off appearing unhurt, leaving Mr van der Spuy lying in the grass.
Footage of the incident was captured by fellow racer Travis Walker, who was recording the race for a marketing company sponsoring the event.
Mr Van der Spuy was taken to hospital but did not suffer any serious injuries beyond minor concussion and whiplash, despite his helmet shattering with the impact . He was discharged the following morning.
The Red Hartebeest is a large, reddish-fawn antelope which although possessing excellent sense of smell and hearing, has very poor eyesight.
They can reach speeds of around 30 miles per hour and males weight around 23.5 stone (150kg).