Emmanuel Bett edged out countryman Daniel Salel in the tightest of sprint finishes, dipping on the line to win the 12km event in 33:32.
Salel was given the same time, with both athletes missing the world best over the unofficial distance by one second.
Timothy Toroitich of Uganda took third place in 33:48, and Elroy Gelant was the first South African home, ending fifth in 34:51.
While the local contingent were dropped by the foreign stars in the first half, there were six SA men in the top 10.
In the women’s event, race favourite Vivian Cheruiyot lived up to the hype, winning by nearly a minute in 38:22.
Yenenesh Tilahun of Ethiopia was second in 39:17, with local athlete Diana-Lebo Phalula grabbing third place, a further four seconds behind.
Phalula led six SA women into top 10 positions.