Aiken had the round of the day with a 9-under-par 63 and Walters closed with an eagle for a 64. They are both 17-under 198 for the tournament and have a two-stroke lead.
Jin Jeong had a 66 Saturday and is alone in third place at 15-under and Roope Kakko, after a 67, is at 14-under 201. George Coetzee (69 Saturday) and Alastair Forsyth (68) are tied for fifth, four strokes behind the leaders.
Aiken started the day birdie-bogey but piled up nine birdies the rest of the way. Three times he had back-to-back birdies, including on Nos. 17 and 18. His round included a 50-foot birdie putt at 14.
Walters was 7-under through 11 holes before a bogey at the par-3 16th. He had four straight birdies beginning at the eighth hole, completing the run with a 40-foot putt at 11. He finished the round with an eagle at the par-5, 551-yard 18th.
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