Tokyo - Top two seeds Angelique Kerber of Germany and Denmark's Caroline Wozniacki roared to the semi-finals of the $1 million WTA Pan Pacific Open in Tokyo Friday.
Top-seeded Kerber outplayed sixth-seeded Slovakian Dominika Cibulkova 6-3, 6-0 and Wozniacki, a former world number one, overcame Spain's Carla Suarez Navarro 6-3, 6-3 in the quarter-finals.
Kerber, 26, ranked eighth in the world, needed just 61 miniutes to stop the 13th-ranked Slovakian.
Wozniacki, seeded second and reeling from her loss to top-ranked American Serena Williams in the US Open final two weeks ago, outlasted the Spaniard in a bout of long rallies.
Kerber will meet third-seeded Ana Ivanovic of Serbia or Czech Lucie Safarova in the round of four on Saturday.
Wozniacki's semi-final opponent is another Spaniard Garbine Muguruza, who outlasted Australian Casey Dellacqua 3-6, 7-6 (7/5), 6-3.
"Dominika is a good player and I knew I needed to be 100 percent. Everything went good and I'm happy to be in the semis again," said Kerber, who finished runner-up to Czech Petra Kvitova in last year's Pan Pacific Open.
"We had long rallies and at the end it was all about trying to play chess out there, really," said the 24-year-old Wozniacki, the world number nine, who reigned at the top of women's tennis in 2010 and 2011.
"We opened up the court and tried to go for winners when we could," she added. "We were just trying to outplay each other."
The two players broke each other's serve seven times in the first set.
After 2-2 in the second set, the Dane broke the 26-year-old Suarez Navarro in the fifth and seventh games before the world number 19 Spaniard pulled one back.
In the ninth game, Wozniacki yielded no point as Suarez Navarro smashed wide from the net, double-faulted and hit a forehand long to end the match in nearly 100 minutes.
In the doubles semi-finals, the top-seeded pair of Cara Black of Zimbabwe and Indian Sania Mirza defeated Serbia's Jelena Jankovic and Arantxa Parra of Spain 6-3, 6-2.
Results from the WTA Pan Pacific Open in Tokyo on Friday (x denotes seeding):
Garbine Muguruza (ESP) bt Casey Dellacqua (AUS) 3-6, 7-6 (7/5), 6-3
Caroline Wozniacki (DEN x2) bt Carla Suarez Navarro (ESP x8) 6-3, 6-3
Angelique Kerber (GER x1) bt Dominika Cibulkova (SVK x6) 6-3, 6-0
Ana Ivanovic (SRB x3) bt Lucie Safarova (CZE x7) 6-3, 6-2
Cara Black/Sania Mirza (ZIM/IND x1) bt Jelena Jankovic/Arantxa Parra Santonja (SRB/ESP) 6-3, 6-2