Lydia Ko carded a first round 66 to claim a share of the LPGA Founders Cup after Thursday's weather-disrupted first round.
The 17-year-old world number one – the youngest player in the history of golf to claim that accolade – carded four birdies on the front and three on the back nine before notching a bogey at the seventh, her only dropped shot of the day.
Joining her on six-under and tied for the clubhouse lead are Germany's Sophia Popov and Americans Kim Kaufman and Tiffany Joh.
After her round, New Zealander Ko hinted that her round could have been even lower.
"I think I had like three (putts) that were perfectly on line but I left it short, and that three-putt on seven," she told reporters from the clubhouse.
"But I guess everything balances out.
"I hit the pin with my chip in 18 – that could have been a much further par putt. So I think six-under is a good start and I just have got to take the positives out of it."
With about half of the field still to finish their rounds, play was called off for the day due to darkness, after overnight rain resulted in a four-hour delay to the start earlier in the day.
Ko added that playing on the rain-softened course had its advantages.
"They weren't really easy," she said.
"But even if we were hitting a long club into the greens, because it was soft, it was more receptive.
"I guess you might lose some distance with the drives but then you can be a bit more aggressive on the greens."
Thursday's round was a continuation of a remarkable run of form for Ko, who has now broken par in 21 consecutive rounds on the LPGA Tour.
The Korean-born Kiwi arrived in Phoenix in a rich vein of form, winning the Australian Open and New Zealand Open in back-to-back weeks, before finishing as runner-up behind Park In-Bee at the HSBC Women's Champions in Singapore.
The leading quartet lead South Korea's Chun In-Gee and Thailand's Moriya Jutanugarn by one shot, while Dewi Claire Schreefel was also on five-under through 10 holes.