World number one Dinara Safina of Russia was surprised by qualifier Chang Kai-chen in the second round of the Toray Pan Pacific Open WTA event on Monday.

Safina was forced out of her title defense after she lost 6-7 (5), 6-4, 5-7 to 132nd ranked Chang from Chinese Taipei.

Safina double-faulted in the decisive set to give up a break before Chang converted on her third match point on Safina's forehand error.

Chang, who defeated Kaia Kanepi of Estonia 6-3, 6-3 in Sunday's opening round, will meet Argentina's Gisela Dulko in the third round. Dulko downed Agnes Szavay of Hungary 6-3, 6-0 on Sunday.