LOS ANGELES (REUTERS) - LPGA rookie Jang Ha-na took advantage of a late wobble by world No. 1 Lydia Ko to grab a two-shot lead after the second round of the season-ending CME Group Tour Championship in Naples, Florida on Friday.
South Korean Jang, hunting her first title on the US circuit after ending up second three times this year, birdied four of her first six holes before finishing birdie-birdie for a seven-under-par 65 in the US$2 million (S$2.8 million) event at Tiburon Golf Club.
That left Jang at 10-under 134, two ahead of New Zealand teenager Ko who carded a 67 that was highlighted by eight birdies but damaged by a double-bogey at the par-four 15th and a bogey at the par-three 16th.
Twice major winner Cristie Kerr and fellow American Jennifer Song were a further stroke back at seven under after posting matching 69s.
Though Ko stumbled over the closing stretch, she maintained her grip in the race with Korean Park In-bee for 2015 LPGA Tour honours as she seeks her sixth victory of the season.
Ko is in pole position to clinch the LPGA Player of the Year award, the money list title and retain her number one ranking while Park has a slight edge in the chase for the coveted Vare Trophy for best scoring average this season.
Park, a winner of two major championships this year, returned a 69 at Tiburon to end the second round six strokes off the pace.
American Austin Ernst, who held a one-shot lead overnight after opening with a 66, triple-bogeyed the par-five first on the way to a roller-coaster 73 and a five-under total of 139.