Mexico's world No. 1 Lorena Ochoa surged into a six-shot lead after a terrific third round of 73 in wild, windy weather at the Women's British Open over the Old Course on Saturday.
With gusts reaching 56kph, 26 of the 69 players failed to break 80, but Ochoa had three birdies in the level par round to stand on six-under par 213.
Sweden's Linda Wessberg, the 26-year-old French Open Champion, was one of only three players to break par and a 72 lifted her into outright second place on 219.
Former world number one Annika Sorenstam and France's Karine Icher both shot 77 and were in a four-way tie for third place on one-over par 220.
But 25-year-old Ochoa, who has won 12 times on the LPGA Tour, is now firm favorite to claim her overdue first major.
"It was a great day," said Ochoa, who led by two shots after round one and by one at halfway.
"Before breakfast, I saw that it was blowing really hard and I knew that par would be a great score. I actually enjoyed it. It was a mental battle and now I am very tired but I couldn't be more pleased and I just hope I can play the same way tomorrow," she said.
Ochoa was one ahead at halfway but made an immediate move by holing a 10m putt for the first of her three birdies at the third.
She added two more, at the fifth and 12th as the rest of the field struggled in the wind.
Ochoa's US playing partner, Wendy Ward, and Scot Catriona Matthew, tied for second overnight, both shot 80 and slipped into joint seventh and eight shots off the lead.
Ochoa has won 12 regular LPGA titles, but has never made the major breakthrough.
But she has come close on a number of occasions, losing last year's Kraft Nabisco Championship in a play-off and she was runner-up at the US Women's Open last month.
"This was definitely one of the best rounds of my life," said Ochoa, who comes from Guadalajara. "But I know it is not over. Anything can still happen."
Sorenstam had five bogeys before eventually claiming her first birdie at the par five 17th where she got up and down from the back of the green, and she could still be a threat.
"I'll certainly be trying tomorrow," promised the 2003 champion.
Wessberg had four birdies in her round to raise hopes of a shock win.