Lewis, ranked ninth in the world, has only one career victory. It came last year at the Kraft Nabisco Championship, when she had a 36-hole total of 9-under 135 at the Crossing Course on the Robert Trent Jones Golf Trail.
Karin Sjodin shot a 64, the low round of the tournament so far, and moved into a tie for second place at 136 with So Yeon Ryu, Sydney Michaels and Lindsey Wright.
World No. 1 Yani Tseng is not playing this week, nor is last week's winner Ai Miyazato.
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