'I feel very pleased to be 4-under, sitting here,' said Sorenstam. 'When we teed off this morning, it was very, very windy. I read the weather forecast, and I thought it was going to get worse. You know, I was really looking at par as a good score today.'
Despite the lowered expectations, Sorenstam, who is trying to become the first player to win this event three years in a row, picked up her first birdie of the day on the sixth hole of the Dinah Shore Course at Mission Hills Country Club.
She hit a 4-wood short of the green and chipped to six feet for a birdie at the ninth and made it two in a row with a 10-foot birdie at the 10th to reach 3-under. Sorenstam struggled on the green at the par-4 16th, however, with a two-putt bogey to fall back to minus-2.
Sorenstam recovered quickly and hit her tee shot to 12 feet at the par-3 17th. She drained the putt and knocked a 9-iron inside eight feet for a birdie at the par-4 last en route to the first-round lead.
'It's always great to shoot under-par in a major the first day and get off to a good start,' said Sorenstam. 'Now I feel comfortable. I know you can't win tournaments like this in the first day, but you can lose them. Therefore, I feel happy with a good start.'
It was the first time that Sorenstam broke 70 in the opening round of this event since 1996. She was also the only player in the field to shoot sub-70 on Thursday.
'I'll get a little rest, little later tee time tomorrow, let this round settle,' said the Swede. 'But I feel very, very good.'
Karrie Webb, Laura Davies, Michele Redman and Patricia Meunier-Lebouc finished tied for second at 2-under-par 70.