The 22-year-old from Taiwan and 2010 LPGA Player of the Year replaced Korean Shin on Monday to become the new world No 1

Taiwan's Tseng Yani took the world No 1 ranking in women's golf from South Korean Shin Ji-yai on Monday as the LPGA looked to its season-opener, starting in Thailand on Thursday. Tseng, the 22-year-old who captured the 2010 LPGA Player of the Year award, jumped to the top for the first time in her career after winning the women's Australian Open and the ANZ Ladies Masters over the past two weeks.

"It is so soon," Tseng said. "I wasn't expecting it as quickly as this. I still have another 10 months to go. I just need to be very patient and keep working hard. I still have a lot of things to learn too."

Tseng has already won three of the LPGA's four major titles, needing only the US Women's Open to complete a career Grand Slam.

If she wins it next July in Colorado Springs, Colorado, she will be the youngest woman to complete a career Slam.

Tseng's prior major triumphs include the 2008 LPGA Championship and the 2010 Kraft Nabisco Championship and 2010 Women's British Open.

After off-season concerns due to economic woes, the LPGA secured a 24-event, 13-nation tour for 2011, dropping one event in Mexico earlier this month over security issues but adding new events this season in Chinese mainland and Taiwan.

"We're pleased that golf's global tour was able to withstand the economic downturn," LPGA commissioner Michael Whan said. "We're thrilled to add new ideas and new tournaments in Phoenix, Taiwan and Guangdong province."

New events include the Imperial Springs LPGA in Guangzhou, China's Guangdong province, next August, October's LPGA Taiwan Championship and the LPGA Founders Cup, a 54-hole US event next month at Phoenix, where $1 million goes to charity.

"The addition of Taiwan and Guangzhou events further prove we are truly a global tour," Tseng said. "With the economic downturn, commissioner Whan and his team have done a great job to secure as many events as they did in 2010."

The LPGA season tees off on Thursday at the Honda LPGA Thailand on the Siam Country Club course in Chonburi and continues next week at the HSBC Women's Championship in Singapore.

While Tseng has jumped into the top spot after finishing fifth in the 2010 rankings, she faces a host of challengers ready to knock her from her perch.

Japan's Ai Miyazato is the defending champion in Thailand and Singapore and will try to duplicate her strong start from last year in a bid to rise from sixth in the current rankings.

Shin, who won twice last season in a campaign complicated by an emergency appendectomy early in the season, became only the third year-end world No 1 after retired stars Annika Sorenstam of Sweden and Lorena Ochoa of Mexico.

World No 3 Suzann Pettersen of Norway, a five-time runner-up last season, seeks her first title since the 2009 Canadian Women's Open.

She won at Thailand in 2007, one of five titles she took that season.

Fourth-ranked American Cristie Kerr, the first US player to reach No 1 after winning last year's LPGA Championship by an astonishing 12 strokes, is also a threat to reclaim the top spot.

South Korean Choi Na-yeon topped last year's LPGA money list, won two titles and captured the Vare Trophy for lowest scoring average.

Other South Korean stand-outs include seventh-ranekd I.K. Kim, No 8 Sun Ju-ahn and ninth-ranked Kim Song-hee .

No 11 Michelle Wie, who won last year in Canada, and 10th-ranked Paula Creamer, who won her first major title at last year's US Women's Open, lead a US contingent that includes rookies Jessica Korda and Jennifer Song, both in Thailand on sponsor exemptions.