The top-ranked Mexican shot a 1-over 74 in the final round at the home of golf. She finished with a 5-under 287 total, four strokes better than Jee Young Lee (71) and Maria Hjorth (71). Reilley Rankin (71) was another stroke back at par.

"For me this is the most special round of golf I ever played," Ochoa said. "Hopefully this is the first of many (majors) to come. It was my time."

Annika Sorenstam, who was tied for third going into the final round, finished tied for 16th at 4 over after a 76 that included a 7 at the 17th Road Hole.

Ochoa is the first player to win a first major title at St. Andrews since Tony Lema at the men's British Open in 1964.

Ochoa led the tournament from the ninth hole of the opening round, when she shot a 6-under 67. The only player to master the strong winds, she began the final round with a six-stroke lead and the only player under par.

Her only problem came at the 17th, where her second shot landed in one of the pot bunkers short of the green. The ball was near the steep front side of the trap and she had to pitch sideways into the rough, but she then played a superb short chip to the putting surface and escaped with a bogey 6. She went to the last hole four shots ahead and a par captured the title.

With no sign of the gusts that sent many of Saturday's scores into the 80s, Ochoa continued to make accurate shots to the greens. Birdies at the fifth and sixth holes put her at 8 under. Despite three-putting at the eighth, she made a 25-foot birdie putt at the ninth to reach the turn in 34, 2 under for the day.

From that point, the championship was all but all over. On the three occasions Ochoa dropped a shot, so did her rivals. She won without a birdie on the back nine.

Although she missed a 4-foot par putt at 11, her lead stayed at five because playing partner Linda Wessberg also dropped a shot. The Swede dropped out of contention with a 7 at the par-5 14th after her drive went out of bounds. At one point 3 under, Wessberg finished with a 75 for a 2-over 294.

Ochoa never came under any pressure, even from Sorenstam, a 10-time major champion.

Starting out seven shots behind the Mexican, Sorenstam hinted at a challenge with two birdies in the first six holes. But the charge vanished with three bogeys in the next five and her wayward drive at 17 for a 7 left sliding down the board.