FIRST ROUND LEADERBOARD US unless stated -10 L Ochoa (Mex) -6 M Wie -5 S Prammanasudh Selected others -3 K Stupples (Eng) -2 J Head (Eng) -1 J Moodie (Sco) level A Sorenstam (Swe) +3 L Davies (Eng)

Ochoa's score broke the tournament record set by Beth Zimmerman in 1962 and equalled the US LPGA major best set by Minea Blomqvist in 2004.

The birdie blitz left her four strokes clear of teenage starlet Michelle Wie.

Defending champion and world number one Annika Sorenstam could only manage a round of level par 72.

But the record-breaking round belonged to Ochoa, who described it as "amazing".

She said: "I kept hitting the ball close to the pin and then making putts. It was a really good day and now I just want to do the same in the next three rounds."

The 24-year-old blew a chance to win last year's US Women's Open when she took eight at the final hole.

She added: "You learn from such experiences and next time I hope to make the most of the opportunity."

Wie was also pleased with her start which saw her hit all 18 greens in regulation, despite twice escaping from trees.

"I usually have trouble starting out," said the 16-year-old. "My game was solid today."

Another teenager Angela Park, 17, who is set to turn professional on Monday, fired a four-under par 68.