Australia's Minjee Lee has failed to capitalise on an early birdie blitz to be 10 shots behind mid-way leader Lydia Ko in the CME Group Tour Championship.
As Ko emerged from a form slump with a tournament record 10-under par in the LPGA season finale at Tiburon Gold Club, Lee made a flying start to the second run.
Lee reeled off birdies in three of her first four holes before a bogey on the fifth stalled her momentum.
She carded birdies at the sixth and seven holes but her inward nine was nowhere near as productive.
A bogey on the 11th was countered with a birdie at the last as she signed for a four-under par 68 for a two-round total of 142l.
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Veteran Karrie Webb is two shots behind Lee after shooting 69, the same score as Sarah Jane Smith who sits in a tie for 53rd.
Ko's return to form was as dramatic as it was unexpected as she stormed clear of the field at the midway point of the LPGA Tour's final tournament in Florida.
Ko conjured a 10-under 62 to soar from 16th overnight to a three-shot lead.
Leading the chasing pack on nine-under are Ryann O'Toole of the United States and Korean So Yeon Ryu.
The 19-year-old hasn't won a tournament since July and has largely struggled with her form, prompting a change of caddie and tweaks to her swing.
Thailand's Ariya Jutanugarn, who led the points race before this week, is tied for 19th on four-under.
Overnight leader Shanshan Feng of China, seeking a third straight tournament win, is a stroke ahead of Jutanugarn in 16th place.
