The American came from behind to grab at two-shot lead after the third round of the Navistar Classic, as 17-year-old defending champion Lexi Thompson, leader for the first two rounds, failed to keep up the pace on moving day.

Lewis lies on 15 under par, two shots clear of Angela Stanford (68), and three ahead of Lizette Salas (70).

Koreans Mi Jung Hur (72) and Haeji Kang (67) share fourth place on 11 under, four back, while Thompson now finds herself five back after a disappointing 74. She's in three-way tie for sixth alongside Sarah Jane Smith (68) and Hee Young Park (72).

Lewis, who birdied four of the first five holes in a round which included no dropped shots, said: "I think going into today I knew I needed to make birdies just the way the scores had been all day, and you don't know if you're ever going to start off like that."

Thompson was disappointed with her round, but still very positive about her chances in the final round.

"I'm definitely not out of it. I shot 63 the first day, so if I have a round like that, I can be in contention."