Maria Sharapova returned to No. 1 in the rankings on Monday despite a lopsided 6-1, 6-2 loss to Serena Williams in Saturday's final of the Australian Open.
Sharapova, who overtook Belgium's Justin Henin-Hardenne in the rankings, arrived in Japan to play in this week's US$1.3 million Pan Pacific Open, a tournament she won in 2005.
"I'm excited to get to No. 1 and hopefully I can keep it for many weeks to come," Sharapova said at a news conference on Monday. "At the end of the day, I reached the final of a grand slam in my first tournament of the year."
Sharapova will be joined by Martina Hingis and defending champion Elena Dementieva. In last year's final, Dementieva defeated Hingis 6-2, 6-0 after Hingis upset Sharapova in the semifinals.
"Martina took me out last year," added Sharapova. "Hopefully I can get some revenge this year in the final."
Sharapova, who turns 20 in April, started this year in Hong Kong, where she lost in the final of an exhibition tournament to Kim Clijsters.
Sharapova spent seven nonconsecutive weeks at No. 1 in her career between August and October in 2005, the AP says.
Her performance in Grand Slams last year helped raise her ranking from fourth at the start of 2006 to No. 2 at the end, including semifinals at the Australian Open and Wimbledon, the fourth round at the French Open and her win in the U.S. Open, the AP says.
Other players to watch in Tokyo will be Serbians Jelena Jankovic (21) and Ana Ivanovic (19).
Singles play begins on Tuesday at Tokyo Metropolitan Gymnasium. Sharapova has a first-round bye and won't play until Wednesday.