Ana Ivanovic downs Angelique Kerber, to meet Caroline Wozniacki in Tokyo final

Ana Ivanovic overcame a slow start to beat top seed Angelique Kerber 7-5 6-3 in the semi-final of the Pan Pacific Open on Saturday to set up a title clash with second seed Caroline Wozniacki.

World number 10 Ivanovic, seeded third in the $1 million event, was down 5-3 in the opening set but went on to win 10 of the next 13 games to seal her victory against her eighth ranked German opponent.

"In the beginning it really took me some time to adjust to her game. It wasn't like my previous matches," Ivanovic said. "But once I adjusted and got more aggressive it started to go my way, and I'm really happy with the win today because she's always such a tough and challenging opponent."

The win boosts the former world number one's bid to qualify for the season-ending WTA Finals in Singapore as it did for her opponent in Sunday's final.

Wozniacki, also a former top-ranked player, was the first to book her spot for the final after a tough match against an aggressive Garbine Muguruza.

The Danish player saved 19 of the 23 break points she faced in the match, including all nine in the first set, to win 6-4 2-6 6-2 against the 20-year-old Spaniard. Muguruza gave it her all, hitting 53 winners in the match but was hurt by the 50 unforced errors she committed.

"She was playing really, really well and very aggressively, but I just kept fighting and staying in there, and I think at the end I had just a little bit more energy than she did," Wozniacki said.

Ivanovic is currently number eight in the race for Singapore, ahead of Wozniacki, and both are leading contenders for a spot in the five places left for the event.