REUTERS - World number one Dinara Safina suffered a 7-6 4-6 7-5 defeat by Taiwanese qualifier Chang Kai-chen in her opening match at the Pan Pacific Open on Monday.
The Russian, dumped out of the U.S. Open in the third round earlier this month, struggled from the start against a player 131 places below her in the world rankings.
Safina, whose ownership of the number one spot has been a source of contention after her failure to win a maiden grand slam in 2009, lost the first set tiebreak 7-5.
The defending Tokyo champion, given a first-round bye at the $2 million tournament, rallied to take the second with a thumping backhand, pumping her fist and screeching "Come on!"
But after seizing an early break in the deciding set, Safina's nervousness resurfaced as she tamely surrendered her serve with a double-fault at 5-4 up.
While Safina yelled at herself in Russian, Chang kept her cool and completed the biggest win of her career by forcing Safina into wild forehand on her third match point after two hours and 44 minutes.