By Richard Pagliaro | Thursday, September 24, 2015

Defending champion Ana Ivanovic extended her Tokyo winning streak to set up a quarterfinal clash with the woman who bounced her out of the US Open.

The second-seeded Serbian defeated an erratic Camila Giorgi, 7-5, 6-2, to score her fifth straight win at the Pan Pacific Open.

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Ivanovic will play Dominika Cibulkova for a semifinal spot.

Cibulkova broke serve five times sweeping sixth-seeded Spaniard Carla Suarez Navarro, 6-4, 6-4. It is Cibulkova's third Top 10 win of the season. She knocked off No. 6 Lucie Safarova on grass at Eastbourne before beating then No. 7 Ivanovic in the US Open opening round.

The 48th-ranked Slovak has won three of five career meetings with Ivanovic.

Ivanovic ripped a forehand return winner down the line for triple set point in the 12th game today. Quick off the mark to run down a drop shot, Ivanovic lifted a crafty lob winner in the corner breaking at 15 to take the first set.

Trailing Giorgi 1-2 in the second set, Ivanovic called for coach Nigel Sears, who told his charge: "Keep making her work and keep your head. It's about you not her."

The world No. 12 took the advice to heart reeling off six straight games to seal a 99-minute victory. Giorgi committed 45 unforced errors, including 11 double faults, compared to Ivanovic's 17 unforced error total.

"I'm obviously very happy to have the victory," Ivanovic said in her on-court interview. "It's a very tough match. She generates a lot of power off the ground strokes and serve. I was really happy to stay composed at the end of the set because if you let her play she can play really well."

Ivanovic is playing for her first title since she defeated Victoria Azarenka, Lucie Safarova, Angelique Kerber and Caroline Woznicki to win Tokyo last year.

No. 7-seeded Agnieszka Radwanska topped Elina Svitolina, 6-4, 6-1. The 2011 Tokyo champion, who has never lost before the quarterfinal stage in five Pan Pacific Open appearances, raised her tournament record to 21-5.

Radwanska will take on Karolina Pliskova for a place in the final four. Pliskova pounded 10 aces in a 6-2, 6-4 victory over Japan's Kurumi Nara. The 13th-ranked Radwanska has not permitted a set in three career wins over the 11th-ranked Czech.