(Reuters) - Lexi Thompson overcame an ailing back to fire a four-under-par 67 and take a one-shot lead after the second round of the Meijer LPGA Classic on Friday.

The defending champion moved to 10-under-par at Blythefield Country Club in Grand Rapids, Michigan, a stroke ahead of Canadian Alena Sharp and South Koreans Chun In-gee, Q Baek and Ryu So-yeon.

“I’m not really one to complain about pain because I just fight through it, but yeah, it’s hurting,” Thompson told reporters. “I didn’t really want to pay attention to how bad it was hurting because then it brings more attention to it and it becomes a mind game.”

World number one Lydia Ko and number two Brooke Henderson shot matching 68s and are three behind Thompson at seven-under. The two teenagers are coming off a playoff duel at the Women’s PGA Championship where Henderson claimed her first major title.

"Anybody can win,” Henderson said. “Anybody can make something happen and it just takes two more really good days and hopefully looking at that trophy on Sunday.”

Ko added she was happy with the way she played but said there was room for improvement.

"My ball striking wasn’t as good as yesterday so hopefully it can get better progressively on the weekend,” she added.

(Writing by Jahmal Corner in Los Angeles; Editing by Peter Rutherford)