CAMBRIDGE, Ontario (AP) — Chella Choi ended up on top of the LPGA Manulife Classic leaderboard Thursday at windy Whistle Bear when Belen Mozo unraveled with a closing triple bogey.

Choi shot a 6-under 66, finishing with a birdie on the par-5 ninth. The South Korean player won the Marathon Classic winner last year for her first LPGA Tour title.

Mozo was 7 under before running into trouble on the par-4 18th. The Spaniard finished with a 68.

Second-ranked Ariya Jutanugarn was four strokes back after a 70 in her bid to win three straight events for the second time this season. The 20-year-old Thai player began her latest streak at the Women’s British Open, and rebounded from a knee injury that forced her to withdraw during the Rio Olympics to win the Canadian Pacific Women’s Open on Sunday in Alberta.

Using a driver in competition for the first time since May, she dropped two strokes on the back nine after birdieing the first three holes and making the turn in 4 under.

U.S. Open champion Brittany Lang, second last year at Whistle Bear after winning the inaugural event in 2012 at Grey Silo, was a stroke back at 67 along with South Korea’s In Gee Chun, Spain’s Azahara Munoz and Sweden’s Dani Holmqvist. Lang holed a lob wedge for eagle on the par-5 third — her 12th hole.

Top-ranked Lydia Ko and Canadian star Brooke Henderson each shot 70.

EUROPEAN MASTERS

CRANS-MONTANA, Switzerland (AP) — American left-hander Paul Peterson shot a 6-under 64 for a share of the first-round lead in the European Masters.

England’s Daniel Brooks and Frenchmen Gregory Havret and Mike Lorenzo-Vera matched Peterson at Crans-sur-Sierre Golf Club. Peterson won the Czech Masters two weeks ago.

Masters champion Danny Willett of England topped the group at 65.