NEW YORK, NY, USA - No.4 seed Naomi Osaka is into her first semifinal at the Western & Southern Open after coming back from a set down to defeat No.12 Anett Kontaveit. 

After seeing a closely contested opening set go the way of the Estonian, Osaka raised her level to reel off nine games in a row, firing 29 winners en route to a 4-6, 6-2, 7-5 victory to set up a semifinal clash with Elise Mertens. 

Read more: WTA Insider Live Blog: Naomi Osaka vs Anett Kontaveit

“For me this entire week I have just been speaking about trying to be more positive,” Osaka said of the nine-game run that sparked her turnaround. “So I think just for the first set and honestly a couple of games in the second I was just really being down on myself and super negative.

“For me… if I had to lose a match, I didn't want to lose a match on that note. I just tried to be more positive and pump myself up.”

2020 Cincinnati Highlights: Osaka contains Kontaveit

The victory sends the two-time Grand Slam winner into her second semifinal of the season, after starting the year with a run to the final four at the Brisbane International and recording a third-round finish at the Australian Open. 

Osaka opened her post-lockdown campaign in New York at the Western & Southern Open, where she was pushed to the limit by Karolina Muchova in the opening round before winning 6-7(5), 6-4, 6-2. She had a more straight-forward victory against 20-year-old Dayana Yastremska, routing the No.16 seed in straight sets to book her spot in the quarterfinals. 

There was not much to separate the Osaka and No.12 seed Kontaveit throughout a tight opening set, with neither player giving an inch as they put on a service masterclass: nine of 10 games contested went to the server, and in seven of those the server dropped just one point or fewer.

But it was ultimately Kontaveit who displayed the initiative to create the only break opportunity of the set. She took advantage of a loose service game from Osaka and applied the pressure to take the lead at 3-2, consolidating to make it 4-2. 

In photos: The story of the 2020 Western & Southern Open

Kontaveit looked to be in control as she closed out the set 6-4, and fought her way through to a 2-0 lead. But Osaka flipped the switch a few games later, saving a break point to avoid a bigger deficit and breaking to love at 2-2. The US Open champion raised her level to cut down on her unforced errors as she reeled off six games in a row to take the second set 6-2.

Osaka continued applying the pressure against Kontaveit, and was rewarded with an early break to start the final set with a 2-0 lead. Kontaveit finally broke Osaka’s nine-game run to hold at love, and found her way back into the set as she got the break back, 4-3. Osaka had a fight on her hands as her opponent threatened to bring them to a tiebreaker, but Kontaveit couldn’t halt the former World No.1’s momentum as Osaka closed out the match, winning 4-6, 6-2, 7-5 after an hour and 52 minutes. 

Read more: Mertens speeds past Pegula to make Cincinnati semis

“I just gave myself a lot of excuses. Then I became very down on myself whenever I would miss balls that I thought I shouldn't miss, but then I'm not putting in the effort to correct myself,” Osaka said.

“So that was the direction I was heading in the first set and like the beginning of the second set. And then just to correct myself, I just began thinking of all my regrets, and I have never regretted a match where I have tried my best and lost.”

Up next for Osaka, No.14 seed Mertens awaits in the semifinals after the Belgian eased past American qualifier Jessica Pegula 6-1, 6-3 earlier in the day. Mertens is tied with Osaka in their head-to-head record at a win apiece, with the Japanese claiming the victory in their most recent encounter last year in Osaka.