A year ago, while still on maternity leave and uncertain about her return to elite tennis, Naomi Osaka attended the U.S. Open to participate in a mental health discussion alongside Michael Phelps. During her visit, she took a seat in the stands to watch one of Coco Gauff’s matches.

At that time, Osaka was already contemplating her return to the courts at Flushing Meadows, even considering what she might wear for competition. Fast forward to Tuesday at Louis Armstrong Stadium, where she dominated No. 10 seed Jelena Ostapenko with a score of 6-3, 6-2. She was adorned in lime green from her visor to her dress, complete with bows on her back and shoes, embodying the essence of this summer's “Brat” theme (for those in the know) and showcasing her prowess as a two-time champion and former No. 1 player.

“I believe that being involved in the design of my tennis outfits provides me with a unique strength, particularly for the U.S. Open attire. I feel they tend to be a bit more extravagant. As I was putting on my outfit today, I thought, ‘I hope this isn’t too over the top,’” Osaka remarked with a grin. “I had the tutu, the bow jacket, and it was all green. I felt like everyone was watching me.”

A fellow competitor requested a photograph, to which Osaka responded, expressing her hope that it conveyed a positive impression rather than a negative one, saying, “I hope it was a positive picture (and) it wasn’t, like, ‘Oh, my God, look at her.’ For me, when I put on the outfit, it’s almost like a super suit, so I try to channel that.”

She executed this sentiment effectively on Tuesday, achieving her first victory over a top-10 player in over four years.

Osaka secured titles in New York in both 2018 and 2020, as well as two Australian Open championships in 2019 and 2021. Her match against 2017 French Open winner Ostapenko was notable as it marked the first instance in five years where two former major champions faced each other in the opening round at the U.S. Open, reminiscent of Serena Williams' victory over Maria Sharapova. Another significant match occurred on Tuesday night, where 2020 Australian Open champion Sofia Kenin triumphed over 2021 U.S. Open winner Emma Raducanu with a score of 6-1, 3-6, 6-4.

"Achieving two victories here holds significant meaning for me, especially as I've faced challenges with my confidence throughout the year," stated Osaka, who made her return to competitive play at the Australian Open in January, marking her first Grand Slam event in nearly a year and a half due to mental health breaks and maternity leave. "This moment compels me to reflect and acknowledge, ‘You’ve performed exceptionally well here. There’s no reason you can’t replicate that success.’”

In terms of performance, Osaka excelled, recording no unforced errors in the first set and finishing with just five, which is 16 fewer than her opponent, Ostapenko.

"I distinctly remember thinking, ‘I need to win this match so I can showcase my other color.’ That was crucial for me," Osaka remarked, currently ranked 88th and granted a wild-card entry by the U.S. Tennis Association. "You can expect to see my other color in the next match."

Her next challenge will be on Thursday against Karolina Muchova, the 2023 French Open runner-up, who triumphed over Katie Volynets of the U.S. with a score of 6-3, 7-5.

Among the women advancing to the second round were top seed Iga Swiatek, who overcame Kamilla Rakhimova with a score of 6-4, 7-6 (6), clinching the final five points after facing three set points while trailing 6-3 in the tiebreaker. Also progressing were former major champions Elena Rybakina and Caroline Wozniacki. Fifth seed Jasmine Paolini, a finalist at both the French Open and Wimbledon this year, triumphed over 2019 U.S. Open champion Bianca Andreescu with a score of 6-7 (5), 6-2, 6-4. Meanwhile, No. 11 Danielle Collins concluded her Grand Slam singles career with a 1-6, 7-5, 6-4 defeat to Caroline Dolehide in an all-American clash, as the 30-year-old Collins prepares to retire after this season.

In another notable match, Shelby Rogers, who recently announced her retirement, ended her career with a loss to sixth seed Jessica Pegula, falling 6-4, 6-3. This match took place after four-time major champion Carlos Alcaraz defeated qualifier Li Tu 6-2, 4-6, 6-3, 6-1 in Arthur Ashe Stadium. Pegula is set to face Sofia Kenin next.

Earlier in the day at Ashe, top-ranked Jannik Sinner played his first match since being cleared in a doping case related to two failed tests in March. Although he started slowly, the 23-year-old Italian quickly regained his form, defeating Mackie McDonald 2-6, 6-2, 6-1, 6-2.

Among the seeded players making progress were No. 5 Daniil Medvedev, No. 7 Hubert Hurkacz, and No. 25 Jack Draper. However, No. 11 Stefanos Tsitsipas and No. 19 Felix Auger-Aliassime both faced defeats, along with No. 23 Karen Khachanov, who experienced a loss in the longest U.S. Open match by duration since the introduction of tiebreakers in 1970.

Dan Evans narrowly defeated Khachanov with a score of 6-7 (6), 7-6 (2), 7-6 (4), 4-6, 6-4, in a match that lasted 5 hours and 35 minutes. The final set, where Evans was down 4-0, took 61 minutes to complete, making it the shortest set of the match.

“When you’re a kid, you’re taught to fight until the end. That’s essentially Rule 1. I’ve consistently adhered to that throughout my career,” Evans remarked. “It certainly paid off a bit today.”