Inbee Park fired a 7-under 64 on Friday to move 1-stroke clear of the field with the second round of the inaugural Manulife Financial LPGA Classic suspended for the night due to darkness.
Park ended 36 holes at 9-under-par 133.
Brittany Lang carded a 6-under 65 to move into a share of second place at minus-8. She was joined there by Hee Kyung Seo (68) and LPGA Champion Shanshan Feng (68).
First-round leader Sandra Changkija struggled to a 1-over 72 to fall into a tie for fifth at 7-under-par 135. She stands alongside Karin Sjodin (68), Katie Futcher (67), Kraft Nabisco winner Sun Young Yoo (67), Lexi Thompson (69), reigning U.S. Women's Open champ So Yeon Ryu (65) and Chella Choi (66) in fifth place.
The first two rounds suffered through weather delays. Friday's delay on the Grey Silo Golf Course forced the completion of the second round to be pushed into Saturday morning.
The seven players that need to finish their rounds will return to the course at 6:45 a.m. (et) Saturday.
Park started on the back nine Friday and parred her first four holes. Birdies on the 14th and 16th moved her to 4-under. Park ran three birdies in her next four holes from the 18th.
The 2008 U.S. Women's Open champ birdied the fifth, but gave that stroke right back with a bogey on the par-5 sixth.
Park erased that mistake with a birdie on the eighth to grab a share of the lead. She made it two in a row with a birdie on No. 9 to go one clear.
"I played great today. I hit the ball very well and especially hit my short irons really good, so gave a lot of opportunities and obviously putted very good today," said Park, who needed just 22 putts in round two. "I didn't find the fairways much softer, but the greens are really, really softer than yesterday."
Lang had one birdie through her first six holes, then drained three straight birdie tries from the 16th. Around the turn, Lang again made three consecutive birdie efforts from the fourth to jump to minus-9.
The two-time U.S. Solheim Cupper tripped to a bogey on the seventh to slip back to minus-8. Lang parred the last two to end there.
Seo, last year's U.S. Women's Open runner-up, birdied three in a row from the third. She birdied the ninth to turn at 9-under. After seven consecutive pars, Seo double-bogeyed the 17th, but got one stroke back with a birdie at the last.
Feng parred her first four holes, then birdied three of the next four holes to move to 8-under. She stumbled to a bogey on the par-4 14th, but birdied the last to share second place.
Michelle Wie, who missed the cut in her last five stroke-play events, will make it to the weekend after back-to-back rounds of 1-under 70. This is her first made cut since the HSBC Women's Champion, the third event of the year.
NOTES: Stacy Lewis, a two-time winner this season, fired a seven-under 64 to soar from a share of 70th to a tie for 12th at 6-under-par 136...The cut line has not been set yet, but Pat Hurst, Christina Kim, Amanda Blumenherst, Sophie Gustafson and Ai Miyazato will all have the weekend off.