NEW YORK, NY, USA -- Naomi Osaka booked a spot in her first WTA singles final of the season, as the No.4 seed defeated 14th-seeded Elise Mertens, 6-2, 7-6(5), in their semifinal clash at the Western & Southern Open on Friday.

Former World No.1 Osaka had split her two previous meetings with Mertens, but this time around, it was the Japanese player who overcame a second-set swoon and a series of grueling games to get the better of the Belgian after just over two hours of play.

"I'm really glad that I'm playing this tournament right now, because just having these match plays and being able to figure things out on the court is going to be really helpful," Osaka said, during her post-match press conference.

"This is my first tournament back from quarantine," Osaka added. "So I'm happy that I'm in the finals." 

Playing her first WTA event since a third-round loss to Coco Gauff during her Australian Open title defense, Osaka fought back from a break down in the second set and withstood eight break points in the 6-2, 4-4 game alone, before quelling a sterling challenge from Mertens in the second-set tiebreak.

Mertens, in fact, had 30 winners to 27 unforced errors during the tilt, and those numbers were exactly flipped for Osaka. Osaka, though, steeled herself on the key points of the match, allowing Mertens to convert only three of her 21 break points, while breaking the Belgian five times overall.

In Saturday’s final, Osaka will take on another former World No.1 and two-time Grand Slam champion, Victoria Azarenka of Belarus, who eliminated No.8 seed Johanna Konta of Great Britain in three sets.

"For me, it's really cool to be able to play Vika now, because I played her in the French last year, but I know that probably her best surface is hard court and also my best surface is hard court," said Osaka. "I think it will definitely be a really fun match." 

Osaka got off to a flying start, earning break point at 1-0 with a forehand crosscourt winner, then taking the early 2-0 lead after a netted backhand by Mertens. The Belgian had three chances to get back on serve in the next game, but aggressive play by Osaka pulled the fourth seed through a protracted tussle, and she reached 3-0.

Deep hitting by Osaka allowed her to grit out another break for 5-1, giving the Japanese player a chance to serve out the set. However, the unpredictable variety of shot from Mertens gave her four more chances to attain a service break in that instance, and the Belgian finally took a game off of Osaka’s delivery, polishing it off with a winning dropshot.

However, Osaka quickly regrouped, firing a forehand winner for 0-30 in the next game, and easing to double set point on the Mertens serve. A Mertens forehand forced an error to erase the first, but on the second, the Belgian blasted a backhand wide, giving Osaka the one-set lead.

The second set started in exactly the same manner as the first, with Osaka opening up a 2-0 lead. This time, though, Mertens clawed the break back straight away, getting back on serve at 2-1 with a beautiful backhand winner crosscourt. 

Suddenly, the flat Mertens groundstrokes found more bite, while the Osaka first-serve percentage dipped, and the Belgian clinched another break to move ahead 3-2. A breezy hold for 4-2 consolidated the break, and Mertens, having reeled off four games in a row, was in control.

Osaka charged back, leveling the set again at 4-4 after she finished off that service break with a backhand crosscourt winner of her own. However, the Japanese player found herself in critical danger again in the next game, as she quickly fell behind triple break point.

However, Osaka regained her first-serve prowess at a crucial time, fending off each of those three chances. She and Mertens then engaged in a protracted game, where Mertens ended up holding eight break points in total but was unable to capitalize. After saving the eighth chance with a backhand winner, Osaka went on to close out a much-needed hold, forcing an error for 5-4.

The pair moved into the tiebreak, where Mertens claimed the first mini-break after a strong return to go up 5-4. But Osaka took command from there, powering groundstrokes to force errors from Mertens on the next two points and queuing up match point. There, a return by Mertens went wide, and Osaka sealed the hard-fought second set and match.

2020 Cincinnati Highlights: Osaka ousts Mertens