NEW YORK, NY, USA -- In her first WTA singles match since the tennis hiatus ended, No.4 seed Naomi Osaka of Japan earned a hard-fought victory in the second round of the Western & Southern Open on Monday, overcoming Karolina Muchova of the Czech Republic, 6-7(5), 6-4, 6-2.

"I think the difference [between winning and losing] was probably attitude," Osaka said, during her post-match press conference. "It kind of boils down to attitude, because for me I feel like I'm more open-minded when I'm calm, so maybe if I was upset I wouldn't have been able to apply the things that I knew I was doing wrong."

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In the first meeting between the two combatants, the two-time Grand Slam champion quelled the challenge from the World No.26, rebounding from the whisker-thin loss of the first set to obtain victory after a grueling two hours and 33 minutes of play.

"In the second set I felt more at peace with myself," Osaka stated. "I realized that there are certain balls that I need to go for."

"I feel like I just learned a lot throughout the entire course of the match, and hopefully it's something that I can do at a quicker time rate," Osaka added. 

A quarterfinalist at the Western & Southern Open last year, World No.10 Osaka fired 28 winners in the match, which included a whopping 12 aces, and the former World No.1 claimed 81 percent of points when she got her first serve into play.

Muchova also had 23 winners on the day, but after eking out the first set, the rising Czech was outlasted by Osaka down the stretch and was denied the second win over a Top 10 player in her career.

The duo exchanged breaks in the first two games of the encounter, but after that, both exhibited excellent serving as the opening set progressed, with no more break points allowed by either player. The pair moved inexorably towards a first-set tiebreak, with Osaka holding for 6-5 with an ace, and Muchova countering with deft play to queue up the breaker.

Muchova took an early 3-0 lead in the tiebreak, drawing rally errors from the Osaka forehand. However, the No.4 seed shored up the power from that wing to claw the mini-break back, and then fired a backhand winner crosscourt to reach parity at 4-4.

On the next point, though, Osaka’s sterling groundstrokes were fended off successfully by Muchova, and the Czech eventually ended that point with a winning lob for 5-4. A dropshot winner on the next point gave Muchova two chances to close out the set, and on the second, an Osaka forehand flew wide, giving the unseeded player a hard-fought one-set lead.

It was Osaka, though, who struck first in the second set, claiming a quick break in the first game after Muchova sent a backhand wide to cede the 1-0 lead. A perfect backhand winner into the corner allowed Osaka to consolidate this time around, as she edged to 2-0.

That early advantage would prove to be the decisive factor in the set, as Osaka was never troubled on serve in the second frame, facing zero break points and winning 83 percent of service points during that timeframe.

Serving at 5-3, Muchova staved off one set point to eke out a hold and put the pressure back on Osaka. However, the Japanese player was solidly up to the task, cracking backhand crosscourt winners in the first two points of the game, then firing an ace to complete the love hold and level the match at one set apiece.

In the decider, Osaka claimed a break in the opening game once more, and then erased two break points in the subsequent game to hold on for 2-0. After surviving that test, the fourth seed took control of the match by coming out on top in a long game, earning the double-break lead over a suddenly error-prone Muchova.

Osaka would not rescind that advantage, smoothly moving to a commanding 5-1 lead. Muchova extended the match with a hold for 5-2, but Osaka closed out the match at her first time of asking, ending the affair with a thunderous ace, her twelfth of the day.

Osaka will face No.16 seed Dayana Yastremska of Ukraine in the third round.

2020 Cincinnati Highlights: Osaka overcomes Muchova