TOKYO - French Open champion Garbine Muguruza exacted revenge for a shock early exit at the US Open by thrashing Anastasija Sevastova to reach the Pan Pacific Open quarter-finals on Thursday.

The Spanish world number three, beaten in the second round by Sevastova in New York earlier this month, spanked the Latvian 6-3, 6-3 to storm into the last eight in Tokyo.

"It was a surprise to play her as the last match was also against her but guess I got my revenge," said Muguruza after victory over a player who was so depressed about the state of her game back in 2013 that she retired. "That's tennis. I'm happy to be the top seed here, it means I'm improving," the Spaniard added.

Belarusian qualifier Aliaksandra Sasnovich upset US Open finalist Karolina Pliskova, the world number six, 6-4, 6-2 to set up a quarter-final with Japanese teenage sensation Naomi Osaka. "I was ready to go to Wuhan (for my next tournament)," said Sasnovich. "But that's life: this is tennis and the ball is round," she added after bouncing the Czech, her first triumph over a top-10 opponent. Elsewhere, Poland's Magda Linette battled to a 4-6, 6-3, 7-5 victory over Kazakhstan's Yulia Putintseva and will next face former world number one Caroline Wozniacki of Denmark.

Cepelova advances to Korea Open quarterfinal: Jana Cepelova of Slovakia on Thursday advanced to the Korea Open quarterfinals after beating the top seed and defending champion Irina-Camelia Begu.  Cepelova, currently the world number 102, defeated the world 23 Begu, who had won two titles at the Korea Open, 6-3, 4-6, 6-3 in 125 minutes.  Cepelova previously made it into the semi-finals at the WTA Tokyo last week before being ousted by Christina McHale in the final.

The 23-year-old Slovak also beat Begu in the two ladies' first and previous match at the qualifiers to the 2013 US Open.  Begu was seeking redemption after suffering four consecutive first-round exits, including at the Rio Olympics and the US Open, since winning the title at the WTA Florianopolis in July.  Cepelova will next play Monica Niculescu from Romania.

Jankovic sails through to Guangzhou semis: Defending champion Jelena Jankovic of Serbia beat Germany's Sabine Lisicki in the quarter-finals of the WTA Guangzhou International Women's Open Thursday, getting her a step closer to the $226,750 top prize.

Second seed and former world number one Jankovic beat 2013 Wimbledon finalist Lisicki 7-6 (7/4), 6-4 to advance to Friday's semi-finals, where she will face third seeded Croatian Ana Konjuh. The tournament's two US players took a beating, with Konjuh knocking out American Jennifer Brady 6-4, 7-5 and Ukranian Lesia Tsurenko securing a win over fifth seed Alison Riske 3-6, 6-4, 6-0 in a match that lasted nearly two hours.

Viktorija Golubic of Switzerland, fresh off a surprise win 6-7 (7/9), 6-3, 6-4 against top seed Sara Errani that had shot her into the quarter-finals the night before, couldn't recreate the magic, losing 6-4, 4-6, 6-3 to Anett Kontaveit of Estonia, listed as 129th in the WTA singles rankings.

Wawrinka marks St Petersburg debut with win: Top seeded US Open champion Stan Wawrinka made a successful Saint Petersburg Open debut Wednesday, cruising comfortably into the last eight by beating Lukas Rosol of the Czech Republic.

Wawrinka prevailed 6-3, 6-1 in just 57 minutes to record his sixth win over Rosol in as many meetings. The world number three raced through the first set, courtesy of service breaks in the fifth and ninth games.

The 31-year-old was checked in the first game of the second set when he was trailing 0-40, but the Swiss star rallied to produce two more breaks to seal the set and the match. "I think my level today was good," Wawrinka said. "I was really focused trying to be aggressive, trying to find the right way for the first round. And I'm happy with my performance."

Fourth seeded Spaniard Roberto Bautista Agut battled back from a set down to advance into the quarter-finals by beating Ricardas Berankis of Lithuania 4-6, 6-1, 7-6 (7/2). "It wasn't easy for me to play the first match here," said the Spaniard. "It was tough to get used to the conditions, the balls and the surface. Hopefully I will perform better in the quarters."

Joao Sousa of Portugal, seeded eighth, also overcame a one-set deficit to beat Moldovan qualifier Radu Albot in a tough three-setter 3-6, 6-4, 7-5 on his way to the second round.

Seventh seed Serb Viktor Troicki experienced few troubles in his opening round match seeing off Portugal's Gastao Elias 6-1, 6-2. Sousa will next face Russian wildcard Andrey Rublev, while Troicki takes on compatriot Dusan Lajovic.