Lexi Thompson, In Gee Chun share Meijer LPGA Classic lead

BELMONT, Mich. (AP) Her ailing back a bit better, defending champion Lexi Thompson shot a 5-under 66 on Saturday for a share of the Meijer LPGA Classic lead with In Gee Chun.

Thompson birdied five of the first 13 holes at Blythefield in her bogey-free round to match Chun at 15-under 198. The 21-year-old American birdied three of the four par-5 holes and is 9 under overall on the par 5s.

Thompson won the Honda LPGA Thailand in February for her seventh LPGA Tour title. The long-hitting Florida player, ranked fourth in the world, also won a Japan LPGA event last month. The back pain could be a major concern heading into the busy summer schedule and golf's return to the Olympics.

Chun had a bogey-free 65, making four birdies in a five-hole stretch on the back nine. The U.S. Women's Open champion sat out a month this year because of a back injury after was struck by a suitcase that rival South Korean player Ha Na Jang's father dropped down an escalator at the Singapore airport.

Sei Young Kim was a stroke back after a 65.