Gatebe, the former SA marathon champion, will lead the local charge against a strong group of foreign athletes targeting a R1 million bonus for the men's record of 3:03:44 set by Thompson Magawana in 1988 and the women's mark of 3:30:36 set by Frith van der Merwe in 1989.
"Everything I've done in training has been focused on this," Gatebe said on Friday.
"I'm going to run my own race, be patient and try to win again."
Fellow South African Hendrick Ramaala confirmed he would be aiming for the record in his first ultra-marathon, but he believed the conditions would play a key role.
"We'll have to see what happens during the race, but the weather will be the deciding factor," Ramaala said.
"It looks like it's going to be warm and it probably won't rain, so I'm not too concerned."
National standard marathon record holder Gert Thys is the fastest man in the field, followed by Ramaala - both are 42-years-old - but there is also a strong international contingent taking part.
Kenyan David Barmasai Tumo and Ethiopian Moges Taye have clocked sub-2:10 marathons, while nine of last year's 10 gold medallists are back.
On the women's side, Mamorallo Tjoka of Lesotho, the only elite female ultra-marathon athlete at the pre-race press conference, was confident she could secure her maiden Two Oceans title.
Tjoka has finished in the top four every year since 2010 but has not won the race.
"I think my condition is much better than previous years," Tjoka said.
"I've fixed a lot of problems that I've experienced in previous runs, and if the weather is good I think I'll have a good performance."
She will face a strong line-up which includes four women - defending champion Thabita Tsatsa of Zimbabwe, Shitaye Gemechu Debellu of Ethiopia, and Russian twins Elena and Olesya Nurgalieva - who have run under 2:30 in a 42km race.