South Korean Narin An set a hot pace as all four Australian hopefuls made promising starts to the LPGA's rich and prestigious season-ending Tour Championship in Florida.
Minjee Lee and Grace Kim both fired four-under-par 68s to trail An by four shots after the opening round as the world's premiers golfers hunt a record $US4 million ($A6.18 million) winner's pay day in Naples.
Lee and Kim are tied for 11th in the elite 60-player field, with Gabriela Ruffels and world No.5 Hannah Green a further shot back at three under and equal 17th.