South Africa’s Hatherly, 23, beat American Howard Grotts into second. United Kingdom’s Tom Pidcock completed the podium.
“I tried the same thing last year, but this year I managed to avoid any rogue pieces of glass and the puncture which ended my race in 2019,” said Hatherly.
“I’m super happy with my form. I’m focusing on cross-country racing this year so, I’m skipping the Cape Epic. But it was still great to race here and test my legs.”
Germany’s Rieder beat fellow countrywoman Lia Schrievers into second, with Swiss Sina Frei placing third.
“I was super excited to race today. When I had the gap in the technical uphill I just thought ‘okay, now I go’, and I think that was nice, because it was a good leg-loosener for Epic,” said the 30-year-old Rieder.
“It’s so special to race between all these children, they’re cheering and it’s a nice atmosphere. It’s super special.”
This event is traditionally served as a spectator-friendly appetiser for the Epic, which kicks off with a prologue on Sunday.
View more provisional results below:
Men (30 minutes + one lap)
1. Alan Hatherly
2. Howard Grotts
3. Tom Pidcock
Women (20 minutes + one lap)
1. Nadine Rieder
2. Lia Schrievers
3. Sina Frei