SEOUL, South Korea – Top seed Jelena Ostapenko sent a firm message to her rivals for the KEB Hana Bank-Incheon Airport Korea Open as she comfortably defeated Nao Hibino 6-2, 6-2 to progress through to the quarterfinals.   The French Open champion won her first match as a WTA Top 10 player on Tuesday, when she beat Johanna Larsson in straight sets, and she wasted little time against Hibino, showcasing her powerful groundstrokes to earn a break in the opening game.   Despite serving just 35% of her first serves successfully in the first set, she remained in control and powered her way past her 22-year-old opponent, adding a second break of serve in the seventh game.

Things got little better for Hibino in the second set as she was once again broken at the first opportunity, Ostapenko firing a devastating backhand down the line to put herself firmly in control of the match.   Although the Latvian would wrestle with her serve for the duration of the match, she continued to make great inroads into Hibino.   The World No.72 showed moments of doggedness, but as her opponent raised her intensity in the fifth game of the set she was broken to love.   Hibino got some reprieve in the following game, in which she broke following a 12-minute battle, but Ostapenko responded immediately before closing the match out with another fierce backhand.

The 20-year-old is now into her seventh quarterfinals of the year, and, ranked No.8 on the Porsche Race to Singapore leaderboard, has consequently stepped up her challenge to qualify for the BNP Paribas WTA Finals Singapore presented by SC Global.   Next up for Ostapenko is Veronica Cepede Royg, who defeated Kristie Ahn 4-6, 6-4, 6-4 earlier on Thursday.   There were also second-round victories for No.4 seed Sorana Cirstea over Nicole Gibbs, and qualifier Priscilla Hon, who defeated fellow qualifier Arantxa Rus.   "I'm happy of course, today was a tough match -- tougher than the score showed," Cirstea said after the 6-3, 6-3 victory. "I'm happy with the way I handled myself, with the way I played important points. It's nice to be in a quarterfinal again and play for the semis."   It's a unique situation for Cirstea in the South Korean capital this week, as she played Gibbs for the first time on Wednesday, and has never faced her quarterfinal opponent -- Thailand's Luksika Khumkum -- on tour either.   "It's never easy to play someone for the first time," Cirstea said. "You watch some videos before, speak with your coach and make a plan. Today was the first time I played Nicole, and my next opponent, I've seen her around, I kind of know her."