Five-times major winner Park put herself in prime position to claim one of the few titles missing from her glittering resume by producing a third bogey-free round of the week as she fired a four-under-par 68 on Saturday for a 13-under 203 total.
New Zealand teen Ko and world number three Lewis were tied at 11-under after both made the most of slightly cooler temperatures in steamy Singapore to fire 67s.
The tricky Serapong Course on Sentosa Island has tripped up many but Park has negotiated her way around 54 bogey-free holes in an exemplary display. "I hit a lot of shots really close and probably could have made a couple two, three more. Hopefully my putter works tomorrow," said the South Korean.
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