Wozniacki crashes out in Tokyo
The 21-year-old Wozniacki, bowed to the 43rd-ranked Estonian 7-5, 1-6, 6-4 in the third round.
Meanwhile, second-seeded Maria Sharapova earned a hard-fought 7-6 (4), 7-6 (4) win over 13th-seeded Julia Goerges of Germany.
Sharapova came back from a 1-3 deficit in the first set and from a 3-5 hole in the second. She will face fifth-seeded Petra Kvitova.