Gloria Park and Eun-Hee Ji shared second place at 65 and Young Kim and Eva Dahllof were at 66.
"Wow, that was unbelievable," Creamer said. "What did we shoot here? Sixty. I didn't know. I didn't realize it."
Creamer said she hadn't realized the Highland Meadows Golf Club course was a par 71, thinking it was 72.
The LPGA record is 59, held by Annika Sorenstam.
Meg Mallon, Anna Acker-Macosko and Jung Yeon Lee have shot 60 on the LPGA Tour.
Creamer had a 27 on the back nine, tying the tour record for nine holes.
Lightning forced suspension of play with 21 players still on the course Thursday.