Wozniacki battles through but Ivanovic falls in Tokyo

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Caroline Wozniacki was taken the distance by Angelique Kerber en route to the Pan Pacific Open semi-finals, but defending champion Ana Ivanovic was defeated by Dominika Cibulkova on Friday.

Top seed Wozniacki has fond memories of the tournament in Tokyo having won in 2010 and reached the final 12 months ago when she was beaten by Ivanovic.

And the Dane remains on course to reach another final after beating fifth seed Kerber 6-2 2-6 6-3.

Having breezed through the opener in just over half an hour, Wozniacki struggled with serve in the second set and was broken three times by a resurgent Kerber.

Kerber was unable to make the most of a break at the start of the decider, as Wozniacki hit straight back and found the crucial break in game eight.

Awaiting in the semi-finals is eighth seed Belinda Bencic, who saw off third Garbine Muguruza 7-6 (7-1) 6-1.

A repeat of last season's final was on the cards, but second seed Ivanovic failed to hit top form in a disappointing 7-6 (7-5) 6-3 loss to Cibulkova.

Cibulkova now comes up against 2011 champion Agnieszka Radwanska in the last four, the Pole having prevailed 7-5 6-2 against Karolina Pliskova.