TOKYO: Former world number one Caroline Wozniacki battled from behind to beat Jarmila Gajdosova 4-6, 7-5, 6-3 at the WTA Pan Pacific Open on Thursday in her first match since losing in the US Open final.

The 24-year-old Dane, seeded second, needed two hours and 11 minutes to oust the Australian qualifier and bool< a quarter-final spot against Spain`s Carla Suarez Navarro.

`She was playing very well. I was trying to fight for every point and it took me a little while just get into it,` said Wozniacki.

`She was hitting a very heavy ball. I was playing a little bit too short and that gave Jarmila opportunities to play very aggressive.` Wozniacki lost the US Open final 6-3, 6-3 to topranked American Serena Williams at Flushing Meadows two weeks ago.

Gajdosovo, ranked 91st in the world, who has never won in her previous six matches with Wozniacki, broke her serve in their opening game. But the Dane immediately broke her back.

The 27-year-old Australian surged to 5-4 by breaking the Dane after five deuces and keeping her next serve to take the first set.

The two players broke each other early in the second set and went tit-for-tat until Gajdosova lost her serve with erratic shots in the 12th game.

After losing her serve at the start of the decisive set, Wozniacki broke the Australian three times and yield no point in the ninth game, banging in a two-handed backhand across the court on match point.

In earlier second-round matches on the day, Spaniard Garbine Muguruza upset fourth-seeded Jelena Jankovic of Serbia 7-6 (7/4), 6-4 in almost two hours.

Another Australian Casey Dellacqua trounced New Zealand`s Marina Erakovic 6-2, 6-4.

Eighth-seeded Suarez Navarro beat Russian qualifier Daria Gavrilova 7-6 (7/5), 6-3.

Dellacqua and Muguruza will clash in the quarter-finals on Wozniacki`s side of the draw with Germany`s world number-eight Angelique Kerber heading the other half as the top seed.

KIRILENKO REACHES LAST EIGHT SEOUL: Russia`s Maria Kirilenko reached her first quarter-final of the year on Thursday when she came from behind to beat Czech third seed Klara Koukalova at the WTA Korea Open.

The former world number 10, who has fallen out of the top 100 this year because of a knee injury, dropped the first set 6-7 (4/7) but she bounced back in style.

She won the second set 6-4 before an emphatic 6-0 victory in the third sealed her first last-eight appearance of the season as her comeback gains momentum.

`To be honest, because I had an injury for a while, my ranking went down,` said Kirilenko, who was out of action for the first three months of this year.

`However it`s not a problem for me. I already know if I start playing well again, my ranl(ing will be going up again, she added.

`It was obviously disappointing to be injured, and I really missed playing, but I had some rest and tried to enjoy my time away. Now Pm really practising and trying hard to get back in my best shape.` The Russian will play sixth seed Kaia Kanepi, who also rallied to defeat Kristyna Pliskova 3-6, 6-3, 6-2, for a place in the semi-finals.

Thursday`s other winners were fourth seed Magdalena Rybarikova, who beat Yanina Wickmayer 6-2, 6-2, and Nicole Gibbs who came from a set down to beat Danka Kovinic 1-6, 6-4, 7-6(5).-Agencies