Tom Sykes' return to testing for Yamaha Italia came to inauspicious halt after just 16 laps when he was forced to withdraw through illness.
The Brit, who is joining Ben Spies for his second outing on the Yamaha around the South African circuit, has been struck by a bug that is sapping him of his energy.
A frustrating early climax for the three-time BSB race winner, Sykes is still hopeful he can get back out on track in the remaining two days.
"All I want to do is go out and get laps in on the bike," said Sykes, "but I'm just drained and have no strength. It's really frustrating because I got here and was perfectly fine. I think I'm finished for the day, after only about 16 laps."
Elsewhere, Noriyuki Haga's debut with Ducati proved eventful after he collided with Ten Kate Honda's Jonathan Rea in the first few minutes. Both riders were unharmed and continued with their programme soon afterwards.
Full report to follow when the first day of testing has concluded.