Fisher and Sterne both shot 4-under-par 68 in the third round but got there in very different paths. Sterne had five birdies and his first bogey of the tournament while Fisher had seven birdies and three bogeys. They are at 19-under 196 and five up on the field after 54 holes.
Jaco Van Zyl had a 5-under 67 in pulling into a tie for third with Felipe Aguilar and Charl Schwartzel, who both shot 68, and George Coetzee, who had a 70 Saturday. They are 14-under for the tournament. Aguilar, from Chile, is the only non-South African among the leaders.
Fisher and Sterne opened the day tied and, after each had first-hole birdies, stayed that way through five holes. Sterne pulled ahead with a birdie at No. 6 and both had birdies at 7 but Fisher grabbed the lead with birdies at 8 and 9.
However, the lead swung back to Sterne when Fisher had bogeys at 10 and 11 while Sterne birdied 11 for a two-stroke edge. Back-to-back birdies by Fisher at 12 and 13 put him back into a tie for the lead.
Both players had bogeys at 15 -- it was Sterne's first of the event -- and had birdies at 18.
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