"My heart was beating," Sorenstam said after shooting a 1-over-par 71 in the Colonial tournament in Fort Worth, Texas. "I felt sick in my stomach. My hands were sweaty."
Sorenstam did more than compete Thursday. She played well, birdieing her fourth hole and then hitting nine pars in a row.
"I'm very pleased," she said.
There were some, including defending Colonial champion Nick Price, who were critical of Sorenstam's decision to play. But she had support of the huge gallery Thursday.
"I certainly enjoyed it, and I hope she makes it to Sunday," spectator Blaine Sanders said. "I'll be here to see it."
Sorenstam said she's playing simply to test herself, adding that she never expected her appearance to turn into golf's biggest event since the debut of Tiger Woods.
One of the people cheering Sorenstam in North Carolina was Southern Pines resident Peggy Kirk Bell, a former playing partner of the last woman to compete on the PGA Tour, Babe Didkrikson Zaharias.
Bell also knows Sorenstam. She enjoyed the unique perspective Thursday of a person who has played golf with both Sorenstam and Zaharias.
Zaharias teamed with Bell in 1950 to win the International 4-Ball Championship. "The Babe," who played in a men's tour event in 1945, is considered the greatest female athlete of all time -- and a character on the golf course.
"If she would hit a good one over a tree or something, she'd turn to the gallery and say: 'Don't you fellas wish you could do that?'" Bell said.
Bell described Sorenstam as a "quiet girl who is very serious about her game" -- the polar opposite of Zaharias in personality. But Bell said the two women share a competitive spirit.
"It was competition that Babe wanted," Bell said, "and I think that Annika wants competition.
"She's there to prove something to herself. ... She'll handle it O.K., and I think she'll make the cut."
The ladies at Bell's golf school in Southern Pines got an extended lunch break Thursday. Bell announced they weren't going back to the course until Sorenstam finished her round at the Colonial.
So more than 100 ladies sat and cheered Sorenstam, just as many more cheered her in person in Fort Worth.
"I've never never had so many people cheer for me," Sorenstam said.
If she plays Friday like she played Thursday, she can enjoy the cheers through Sunday.