World number one Caroline Wozniacki was knocked out of the third round of the WTA Tour Pan Pacific Open with a three-set defeat to Estonian Kaia Kanepi.
Kanepi, ranked 43 in the world, stunned Wozniacki with a 7-5 1-6 6-4 victory in Tokyo.
Wozniacki, 21, was the reigning champion and playing her first tournament since losing in the US Open semi-finals two weeks ago.
It was unseeded Kanepi's first win over Wozniacki in three attempts.
Wozniacki is without a tournament victory since winning the Danish Open in June.
On the eve of the match, Wozniacki revealed she had received a golf club from boyfriend Rory McIlroy, inscribed 'Wozzilroy'.