Maria Sakkari shook off any lingering disappointment from last year’s round-robin exit and powered Greece to a fast start at the 2026 United Cup in Perth on Friday, earning a marquee straight-sets win over four-time Grand Slam champion and World No. 16 Naomi Osaka.

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When paired with a Stefanos Tsitsipas victory over Shintaro Mochizuki a couple hours later, the result was a resounding victory for Greece, giving them an early advantage over Japan and Great Britain in Group E.

Facing Osaka for the first time in nearly five years, Sakkari jumpstarted Greece’s opening tie against Japan with a 6-4, 6-2 victory in 1 hour and 38 minutes.

“You’re always very hesitant when you come in that first match because sometimes you can trick yourself that you had a good preseason, and then you have high expectations to come out and do everything,” Sakkari told reporters after the match. “I really forced myself not to think like that. I think that was the key. Just went out there, tried to do the things that I worked on and, you know, we keep building and we can keep trying to improve.”

Sakkari struck first in the opener, racing out to a 2-0 lead with a hold and an early break in Osaka’s opening service game. Osaka broke back immediately, but Sakkari reclaimed the advantage and closed out the set, painting the line with a backhand winner to set up a third set point, which she promptly converted.

“[There were] a lot of backhand winners, but a lot of backhand errors as well,” Sakkari said. “I have to allow myself to miss in order for me to make a lot of winners. It was all about who was going to take the backhand line. It was all about who was going to get that good crosscourt ball in order to get down the line.”

They traded holds at the start of the second set, before Sakkari erased two break points for a 2-1 lead. She then managed to break Osaka again to move in front 3-1. The World No. 52 maintained control from there, sealing her third win in six meetings with Osaka to even their head-to-head and, more importantly, give Greece a 1-0 lead in the tie.

“Honestly, I thought it wasn’t a bad first match for what it was,” said Osaka, who admitted she’s been battling an aggressive cold. “I definitely could have been more aggressive on the returns, and I think I did that a little bit towards the end, but [I’m] learning not to be afraid of mistakes, and kind of just going for it from the beginning.”

Shortly after that match concluded, Tsitsipas launched his own 2026 campaign on a positive note, guiding Greece across the finish line.

Playing his first match since last September after a layoff caused by a back injury, Tsitsipas looked strong in a commanding 6-3, 6-4 win over Mochizuki.

“It’s been a rough few months for me,” Tsitsipas said. “I was in a lot of uncertainty, and I was not sure if I could really compete, so to see myself at that level again and showing some really good tennis is something I’m grateful for. Let’s keep it going.”

After a second-round loss to Matteo Gigante at Roland Garros last year, Tsitsipas dropped outside the Top 20 of the PIF ATP Rankings for the first time since August 2018. He battled a back injury throughout the season and briefly worked with Goran Ivanisevic for two months before rehiring his father, Apostolos. 

But in his season debut, Tsitsipas looked refreshed and purposeful, striking the ball with conviction in his first career meeting with the 22-year-old Mochizuki, the World No. 99.

Once a Top 10 fixture, Tsitsipas now sits at No. 36 in the world and has targeted a return to a major final in 2026, having previously reached that stage at Roland Garros in 2021 and the Australian Open in 2023. 

In the mixed-doubles match, Sakkari and Tsitsipas defeated Nao Hibino and Yasutaka Uchiyama 6-2, 6-3 to complete the 3-0 sweep.