Naomi Osaka continues to roll at the Miami Open, easily taking down No. 13 seed Angelique Kerber in a 6-2, 6-3 victory.

The one-hour victory is a big one for Osaka, who was 1-4 in career head-to-head matches against Kerber and had lost the past four against the former world No. 1. Kerber is one of two women to defeat the four-time Grand Slam champion four times, alongside Simona Halep.

“She’s like the first high-seeded player I’ve beaten this year,” Osaka said in her on-court interview. “I feel like I came into the match wanting to dictate. My power on the shots was working really well.”

Next up, Osaka will face off against Karolina Muchova, who upset No. 18 Leylah Fernandez 6-4, 7-6 (7-3). The previous two matches between Muchova and Osaka are split down the middle, with Osaka calling her “one of the most athletic players on tour.”

“It’s going to be a really fun match I think,” she added. “I know we both really want to win it.”

Elsewhere, the Miami Open was ripe with upsets as Aryna Sabalenka, Emma Raducanu, Anett Kontaveit, Elina Svitolina and Karolina Pliskova all lost their Round of 64 matches.

The No. 1 seed in the tournament, Sabalenka was stunned by Romanian Irina-Camelia Begu, losing 4-6, 4-6. The match gave Begu her first Top 10 win since 2018.

Sabalenka struggled, making 34 unforced errors to her opponent’s seven, and couldn’t find range from the baseline. She also was unable to break Begu’s serve, going 0 for 6 on break points during the match.

Raducanu bowed out in three sets (6-3, 4-6, 5-7), taking the first over Katerina Siniaková before dropping the final two sets.

Kontaveit lost to American Ann Li, 0-6, 6-3, 4-6, while Svitolina also took her match against Heather Watson to three sets and a breakpoint, 6-4, 3-6, 6-7 (9-7). Pliskova managed 10 aces against Anna Kalinskaya but was plagued by nine double faults, losing 3-6, 3-6.

After Thursday, just three seeds in the top half of the draw remain: No. 8 Ons Jabeur, No. 9 Danielle Collins and No. 22 Belinda Bencic

The US Open kicks off this week in New York City with a full house of spectators expected to attend. Fans won’t have the honor of watching either of the Williams sisters take the court, as both have withdrawn due to injury. But with Ash Barty and Naomi Osaka both in top form, viewers will be witness to two young stars whose zeniths could finally collide on the grand stage — if they can survive the array of talented competitors that stand in their way.

Here’s who to watch in New York during tennis’ final Grand Slam of the year:

The Favorites

Australia’s Ash Barty is heading into the US Open with all the momentum one could hope for at this point in the North American hard-court season.

The world #1 in rankings recently became the first player to claim five WTA singles titles in a single season since Serena Williams did it in 2014. That fifth trophy came last week at the Western & Southern Open in Cincinnati, where Barty worked her way through several Grand Slam contenders on her way to the title, including Victoria Azarenka, Barbora Krejcikova, and Angelique Kerber. When the 25-year-old won Wimbledon earlier this summer she proved her inaugural Grand Slam title at the 2019 French Open and subsequent number one ranking that persisted through the strange landscape of the pandemic were no fluke. But she has yet to reach the finals rounds of a US Open. Having lost in the round of 16 in both 2018 and 2019 and then opted out in 2020 due to the pandemic, she is poised to make a very deep run this week in New York.

The woman most likely to rain on the 2021 Barty parade is none other than Naomi Osaka. While her trajectory this year has been much more of a roller coaster, she has four hard-court Grand Slam titles to Barty’s zero. Out of the last four Grand Slam tournaments held, Osaka won the first two and then either withdrew or opted out of the next two. She hasn’t lost a single Grand Slam match since January 2020 at the Australian Open, way back in the Before-COVID-Times. Both she and Barty lost early at the Tokyo Olympics, but Osaka also lost in the round of 16 at the Western & Southern Open. Off the court, she continues to figure out how and whether she wants to meet current expectations of a highly publicized life. Only she knows the extent to which those struggles may be impacting her play.

Barty and Osaka are tied 2-2 in head-to-head matches. Even though Osaka dropped a spot from #2 to #3 in overall rankings last week, her and Barty are fortunately on opposite sides of the bracket. Even with a rocky lead up to the last Grand Slam of the year, Osaka is a proven champion with a stellar hard-court record and has a solid claim to the title of best women’s player in the world. Cheers to the tennis gods for a draw that leaves the door open for a Barty v. Osaka US Open final.

Contenders with momentum on their side

One of the most exciting players of 2021 has been Barbora Krejcikova. The 25-year-old from the Czech Republic just recently broke into the top ten and currently sits #9 overall, by far her best ranking in singles.

Krejcikova entered 2021 with two Grand Slam doubles titles from the 2018 French Open and 2018 Wimbledon and has watched her singles success finally take off. This year, she has won three WTA singles titles, including her first Grand Slam at the French Open. She also managed to capture her second French Open doubles championship that same week and then followed that up with a gold medal in doubles at the Tokyo Olympics. While the clay court seems to suit her well, she’s proving the hard court fits nicely too. She won the first hard-court tournament of the year at the Livesport Prague Open and made it to quarters of the Western & Southern Open before losing to Barty. 

In the #12 spot in WTA rankings, Swiss player Belinda Bencic is also enjoying a breakout 2021. Having won the Olympic singles gold medal and then following it up with a strong run at the Western & Southern Open where she lost in the quarters, Bencic is looking like a solid threat as she heads into her strongest Grand Slam event.

Karolina Pliskova and Angelique Kerber are another two to keep your eye on. Pliskova has gone deep in the two hard-court lead-up tournaments to the US Open and was on the opposite side of the net to Barty in the Wimbledon final. Having made it to the quarters, semis, or final of a Grand Slam eight times, she appears to be on the precipice of finally tipping that scale. Kerber, on the other hand, has experienced Grand Slam title glory three times in her career and with appearances in this year’s Wimbledon semis and the Western & Southern Open semis, she is definitely a threat.

The Question Marks

Aryna Sabalenka, the woman who just surpassed Osaka to claim the #2 overall ranking, is still a bit of an unknown heading into New York. She put her name on the map this summer by making it to the semis of Wimbledon and she also got to the semis of one hard-court tourney early in August, but lost in the first round of another. Whether the 23-year-old from Belarus has something special in store for New York is a bit of a guess.

Bianca Andreescu hasn’t had the strong return from injury that many were looking forward to during this hard-court season. The 2019 US Open champion has had a rough showing for 2021, and her recent hard-court tournaments have been no exception. But at only 21 years old and with a new coach on board she has plenty of time to back up her 2019 victory even if it’s not imminent.

Veterans Simona Halep and Victoria Azarenka will also need a bit of luck on their side in order to make a strong run this week. With injuries and early exists from lead-in tournaments, the stars don’t seem to be aligned for either of the two-time Grand Slam champions. 

US Open first-round play begins Monday, Aug. 30 and continues until the two women left standing face off for the title at 4pm ET on Saturday, September 11th.