The incident happened on Friday night near Glenhazel, said WTSA media consultant Bruce Davidson.
Sithole, ranked number two in the world as a quad wheelchair tennis player, was travelling with his brother on the Newmarket Road onramp around 11.15pm when four armed men in a vehicle in front stopped and attempted to hijack them.
The men dragged Sithole and his brother from their car, and stole their cellphones.
Davidson said although Sithole was shaken and traumatised, he was not physically injured and was recovering well.
"I am glad my car, wallet and my life are still with me," Sithole said while thanking family, friends and fans for their messages of support. Holger Losch, Sithole's coach and WTSA director, said he was thankful.
"We are extremely grateful that Lucas and his brother were not physically injured during the hijacking and will make a speedy recovery from the trauma."