Sorenstam, the first woman in 58 years to play on the tour, was bogey-free until three-putting from more than 60 feet at her 14th hole, the 470-yard No. 5. After her drive hit the right rough and rolled down a hill, she managed to get to the green, but on the opposite side from the cup.
After years of dreaming and three months of hype, Sorenstam was finally playing with the men Thursday to see how her game holds up against the best in the world.
"This is like putting a woman out there in the NFL or in the NBA against the men," CBS Sports golf analyst David Feherty says. "Golfers are too big, they're too strong, they have too many physiological differences, too many advantages over a woman. And it's extremely difficult for her to come out here and compete."
Sorenstam's round started with a drive 243 yards into the fairway at the 404-yard 10th hole. She then slumped in mock relief and laughed before walking down the fairway. After that, she seemed at ease throughout her round.
Sorenstam's 9-iron approach from 143 yards settled just more than 15 feet from the cup and she two-putted for par. She had pars on 12 of her first 13 holes before missing her first fairway.
Sorenstam's lone birdie through 14 holes came on a 15-foot putt off the back fringe at the 178-yard 13th, her fourth hole.
She played 10 more holes before giving that stroke up with her bogey at No. 5, the end of a trio of holes known as the "Horrible Horseshoe" because of its length and shape. The two longest par 4s on the course sandwich a par 3 that plays as long as 246 yards.
Her approach at the 400-yard No. 2 hole was more than 40 feet from the cup. She ran her first putt five feet past the hole, but saved par with a tricky comeback.
When her round started, a crowd of media and fans was stacked 10-12 deep around the No. 10 tee, and the fairway on the 404-yard hole was lined with spectators — many of them women wearing "Go Annika" buttons. Large crowds awaited her at every hole.
The crowd applauded when Sorenstam started the short walk from the clubhouse to the No. 10 tee. After being introduced, she acknowledged the cheering crowd with waves to both sides of the tee before hitting a 3-wood for her drive.
Sorenstam, the No. 1 female player in the world, out-drove playing partners Dean Wilson and Aaron Barber, though the two PGA Tour rookies hit their first shots with irons.
After her birdie at No. 13, Sorenstam again hit 6-iron at the other backside par 3, the 188-yard 16th. She hit to five feet, but her birdie chance slid just right of the hole.
When Sorenstam walked up the 18th fairway after her approach shot bounced off a hump by a bunker onto the green, she got the kind of cheering reception usually reserved for players about to win a tournament. But she wasn't even halfway done with her first round.
Rain the previous two days made the course play its full 7,080-yard length, but also made the normally crusty and firm greens more forgiving. There was almost no wind at the course known for breezy conditions.
Like everybody else, Sorenstam was ready to find out how she scores and how she copes with all the attention of being the first woman since Babe Zaharias in 1945 to play on the tour.
"I can't prepare any more," Sorenstam said Wednesday after her final practice round. "I've been waiting for this day for a long time. I've been practicing a lot the last few months and I want the day to come. It's here. So whatever happens, happens."
Las Vegas oddsmakers gave Sorenstam a 500-1 chance of winning, and they were being generous.
The Colonial layout is a longer, tougher course than any she has played in competition. The LPGA's Corning Classic in New York this week is at 6,062-yard course being played as a par 72.
Sorenstam is under more scrutiny than any player since Tiger Woods made his pro debut in the 1996 Greater Milwaukee Open.
And for the first time in years, Sorenstam started a tournament she is not expecting to win. The 32-year-old Swede said she would be "so pleased" to shoot par.
Sorenstam isn't trying to prove she can beat the boys. She isn't suggesting that the LPGA Tour, where she has won 43 times — she also has won four majors — is no longer a challenge. She is just curious to see how she stacks up, and said a week on the PGA Tour would satisfy her.
"I'm sure she's feeling a lot of pressure, but she's putting it on herself wanting to perform well," said David Toms, who tied for second last year. "She's won big tournaments, won a lot of tournaments, and she obviously handles the pressure very well. It will be interesting to see what happens."
Jay Haas said Sorenstam's debut "might be bigger" than Woods' first pro event.
"Was Tiger's debut spread across the front page of the newspaper?" Haas said. "But it's certainly different. Everyone was talking about Tiger dominating the tour, and they don't think Annika is going to come out here and do that."