OSAKA, Japan - Top seed Naomi Osaka delighted tennis fans in her Japanese hometown on Saturday, cooling off the mercurial Yulia Putintseva in straight sets to reach the semifinals at the Toray Pan Pacific Open. 

The former World No.1, currently ranked No.4, came into the matchup trailing Putintseva in the pair’s head to head record - the Japanese player hadn’t even taken a set in their previous three encounters, including a Wimbledon first-round stunner earlier in the year.  

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But Osaka flipped the script in the city of her birth, and she fired 29 winners and six aces to claim the victory 6-4, 6-4, powering her way into her second semifinal since her Australian Open triumph in January. 

“For me, I learned a lot from when I played her at Wimbledon, and I know that a hardcourt is where I feel most comfortable,” Osaka told press afterward. “And also, I’m playing in Japan, so I thought I had the advantage this time around.”

Osaka seemed to have all of the answers for the first half of the opening set, bossing the rallies and fighting her way up to a comfortable lead, 5-1 with a double break. But Putintseva came charging back, switching up her gameplan and going to the dropshot, to great success, and earned a late break at 5-2.

Putintseva grew in confidence and continued to apply the pressure, holding off Osaka once again as she served for the set, saving a pair of set points and wrestling them back on serve, 5-4.  

But Osaka, who is currently coached by her father Leonard François, dialed back the aggression and cut down on her unforced errors, getting right back on track to halt her opponent’s comeback. Osaka claimed her third break point, breaking a third time to take the opening set. 

Osaka might have felt a sense of deja vu in the second set when, once again, she found herself in danger after building up a big, 4-1 lead. The Japanese player coasted along toward the finish line, holding a match point on Putintseva’s serve at 5-2. 

The Kazakh saved another match point as she set off to mount a comeback, raising her level to break the Japanese player who was serving for the match. Unfortunately, Putintseva rolled her ankle on the third match point, with Osaka serving at 5-4, 40-15. After a lengthy medical time out, Osaka claimed the final point to seal the battle, 6-4, 6-4 in an hour and 46 minutes. 

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“I was really worried for her because ankle injures are pretty serious sometimes,” said Osaka, who was one of the first to reach Putintseva and offer her support. “So I didn’t want it to end her Asian season, I guess. I kind of just ran there.”

Osaka will be back in action later today to face No.9 seed Elise Mertens - who defeated Camila Giorgi in straight sets earlier in the day - as she seeks a third career appearance in the Toray Pan Pacific Open final.