Canadians Brooke Henderson and Alena Sharp shot a 5-under 65 in alternate-shot play to take the first-round lead in the Dow Great Lakes Bay Invitational, the LPGA Tour's first-year team event.
Henderson, from Smiths Falls and Hamilton's Sharp had seven birdies and two bogeys at Midland Country Club.
Paula Creamer and Morgan Pressel were a stroke back.
The team of Calgary's Jaclyn Lee and New Zealand's Robyn Choi were tied for third at 67 with Minjee Lee and Jin Young Ko, Jasmine Suwannapura and Cydney Clanton and Amy Yang and Mirim Lee.
The sister duo of Nelly and Jessica Korda topped the group at 68.