Lorena Ochoa took advantage of unusually calm, sunny conditions at the home of golf Thursday to shoot a 6-under 67 for the early lead at the Women's British Open.
The Mexican made six birdies in a bogey-free round on the day women's professional golf made its debut at St. Andrews, the birthplace of the sport.
By the time Ochoa walked off the 18th green, few players out on the course were threatening her lead.
Japan's Ai Miyazato came in with a 3-under 70. Michelle Wie, having started well with birdies at the third and fourth holes to go 2-under, finished at even 73.
Making three birdies in a row around the turn, Ochoa moved to 4-under and increased her lead to three shots when her long approach to the 15th finished two feet (0.6 meters) from the pin to set up her fifth birdie.
Another birdie followed at the 17th, the famed "Road Hole" which has been made a par 5 for the women. It is a par 4 for the men, who can more easily reach the green in two.
Ochoa's second shot finished at the back of the 17th green, and her first putt left her with a five-footer (1.5 m) for birdie to regain her three-stroke lead. After Miyazato bogeyed the 16th, Ochoa walked onto the 18th green four shots ahead of the field. She just missed a 15-foot (4.5 m) birdie putt at the last.
Miyazato recovered from a double-bogey 7 at the fifth to make four birdies on the back nine.
The Japanese star drove into rough at the fifth, failed to clear a pot bunker with her second and had to play her third shot sideways out of the sand.
Despite pulling her drives far left at the opening two holes, the 17-year-old Wie looked comfortable on her first competitive round here, although she is still not free of pain from her injured left wrist. She rolled in 10 (3 m) and seven-foot (2.1 m) birdie puts at the fourth and fifth holes to move to 2-under.
After winning her first title at the Evian Masters on Sunday, Natalie Gulbis didn't expect to be five shots behind at the turn. Without a birdie on the front nine, the American was 1-over after a bogey 5 at the second and went on to finish at 73, along with Paula Creamer.
Sweden's Annika Sorenstam, who won this championship at Royal Lytham in 2003 and has a total of 10 majors, went out later.