Stacy Lewis and Sarah Kemp both posted under 69s on Thursday as the 2012 LPGA season kicked off with the first round of the Women's Australian Open.

This season also began much like last season went -- with Yani Tseng in contention for the win.

The world's top-ranked player, Tseng posted a three-under 70 on Thursday at the Royal Melbourne Golf Club. She is tied for third with Brittany Lincicome and Julieta Granada.

Melissa Reid, reigning U.S. Women's Open champion So Yeon Ryu, Sandra Gal, Jessica Speechley and Sarah Oh are tied for sixth, two shots behind the leaders after posting 71s.

It's no surprise for Tseng to be near the top of the leaderboard. Last season, she won seven times on the LPGA Tour and 12 times worldwide, and ran away with the tour's money title.

It's also no surprise to see her near the top of the leaderboard at this event, which she won in 2010 and 2011. This is the first year that the Women's Australian Open is being held as an LPGA event.

Lewis posted her round of four-under after overcoming several mistakes. She started from the 10th tee and posted a bogey on No. 11, but then immediately got the stroke back with a birdie at the par-five 12th.

That birdie began a stellar run for Lewis, who also birdied the 13th, 15th and 17th. A bogey at No. 18 sent her around the turn at two-under, but Lewis settled down. She made at least par at every hole on the front nine, with birdies at six and eight.

"Early on it was about as easy as it could play," Lewis said. "Towards the end there, when the wind started blowing, nine and 18, the greens were really firm."

Kemp, on the other hand, played a bogey-free round while also starting at No. 10. She had just one birdie through her first 11 holes, but another at the par-three third help kick-start her move up the leaderboard. She also birdied the fourth and seventh to reach minus-four.

Tseng bogeyed her first hole Thursday, but birdied four of the next eight holes to make the turn at three-under. She ran off seven consecutive pars before a birdie at the par-five No. 8, but she bogeyed her final hole to end the first round outside of the lead.

"It was disappointing to finish with a three-putt on the last hole," Tseng said. "It is probably the toughest hole on the course. But I am still very happy shooting three under today."

American teenage sensation Lexi Thompson, who will turn 17 years old on Friday, shot a 74. She is the youngest winner in LPGA and Ladies European Tour history, having won the LPGA Classic in September and Dubai Ladies Masters in December.

NOTES: Three of the top four players in the world are in the field - Tseng, second-ranked Suzann Pettersen and fourth-ranked Cristie Kerr. The Norwegian Pettersen posted a seven-over 80, while the American Kerr had a two-over 75...This is the first time that the LPGA Tour has played in Australia in over a decade...Christel Boeljon, who won the Australian Ladies Masters last week, also posted 74 on Thursday.