Michele Redman fired a seven-under-par 65 on Thursday to break the course record and grab a one-stroke lead over Annika Sorenstam in the Samsung World Championship.

The American matched the best opening round in tournament history, and broke the Hiddebrooke Golf Club record set one year ago.

"I'm motivated every day I get up," said Redman.

"Now I'm playing so well, it makes it fun also. I just want to play the best I can and see what I can do this year."

Sorenstam notched her third hole-in-one on the LPGA Tour as she began her attempt to become the first player to post nine wins in a season since Nancy Lopez in 1978.

South Korea's Grace Park is two shots back after a five-under 67, while Laura Diaz, Rosie Jones and Cristie Kerr opened with 68s.

The 72-hole event features the top 17 players on the money list as well as the leading money winners from Europe (Paula Marti of Spain), South Korea's Mi Na Lee and Japan's Mikino Kubo.