Former World No.1 Naomi Osaka got her 2025 season off to a winning start with a 6-4, 6-4 victory over qualifier Lina Glushko in the first round of the ASB Classic in Auckland, New Zealand on Monday.

Auckland: Scores | Schedule | Draws

The four-time Grand Slam champion, Osaka needed 1 hour and 25 minutes to hold off Glushko and advance to the second round of the WTA 250 event. Here are some takeaways from Osaka's victory:

Triumphant return after eight years away: Exactly 12 months ago, Osaka came back to action following her maternity leave. Osaka elected to start this season in New Zealand as this week's No.7 seed. 

Osaka had played the ASB Classic just once before, reaching the 2017 quarterfinals as a teenager ranked just inside the Top 50. That year, Osaka advanced past Venus Williams via walkover, then fell in the last eight to Ana Konjuh. 

Much has changed in eight years. Osaka now has four major titles and 21 weeks at World No.1 behind her, and she gave birth to daughter Shai in July of 2023.

"I’m really happy to be back," Osaka said on court, after her win.

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Osaka cooled off qualifier's strong start: Glushko, a 24-year-old ranked No.221, is still a relative newcomer to tour-level matches. This was only her fourth WTA main-draw match, and her first win at tour-level came just last year over Kateryna Volodko in Monterrey.

Despite the disparity in their accomplishments on tour, Monday's match was no cakewalk for Osaka. Glushko made Osaka work in rallies, demonstrating the form that allowed her to win two straight-sets matches in this weekend's qualifying.

Osaka only broke serve once in the first set, where she had to fire multiple crosscourt backhands in a lengthy rally before outlasting speedy Glushko for 2-1.

In the second set, Osaka saw a 3-1 lead slip away as Glushko reeled off three games in a row. But Osaka regrouped to win the last three games of the day, withstanding Glushko's defending, windy conditions and audible protests outside the stadium which briefly halted play in the first set.

"It was good to have to, I guess, scrap a little for the first round," Osaka said.

Stellar serving the key stat: Even during patches where unforced errors got the better of her, Osaka could rely on her delivery to get her through. Osaka fired seven aces in the match, and she won 77 percent of her first-serve points and 64 percent of her second-serve points.

"I just kept trying to tell myself ‘One point at a time,’ and try not to get discouraged," Osaka said. "Thankfully it came out in my favor at the end."

Osaka will hope to maintain this form when she takes on Julia Grabher in the second round. Grabher saved one match point in a 2-6, 6-3, 7-6(7) win over qualifier Leyre Romero Gormaz on Monday.