Rybakina and Muchova cruise; Masarova upsets Sakkari at the US Open

On Day 1 of the year's final Grand Slam, the three Top 10 players in the second quarter of the US Open main draw had mixed results. Elena Rybakina and Karolina Muchova advanced to the second round, while Rebeka Masarova knocked out Maria Sakkari.

In their first-round match on the Grandstand, No.4 seed Rybakina defeated Marta Kostyuk 6-2, 6-1. Kostyuk had beaten Rybakina earlier this year in Adelaide, but Rybakina avenged herself in 1 hour and 27 minutes.

Kostyuk, one of the highest-ranked unseeded players at No.39, won her first two Top 10 matches this summer. Rybakina, who went 5-for-12 on break points, kept her from getting another one. Only one of Kostyuk's five break points was converted.

Rybakina's career-best performance at the US Open is a third-round appearance in 2021. It is the only Grand Slam in which Rybakina has not advanced past the quarterfinals.

Rebeka Masarova in action at the 2023 US Open First Round.

Earlier in the day, Masarova of Spain stunned No.8 seed Sakkari of Greece 6-4, 6-4, earning her first Top 10 victory in the process.

Masarova was 0-4 against Top 10 players coming into the match, but the powerful 24-year-old broke that streak with a one-hour and 27-minute victory over 2021 US Open semifinalist Sakkari.

Masarova trailed 4-1 in the first set, but she won the next five games in a row to take a one-set lead. In the second set, the Spaniard was never broken and cruised to victory. Masarova had three break points in the match, all of which she converted.

In the second round, Masarova will face Anna Karolina Schmiedlova of Slovakia.

Sakkari has been a Top 8 seed at the last eight majors, but she hasn't won a Grand Slam match since the Australian Open this year. Sakkari was eliminated in the first round of this year's Roland Garros by eventual finalist Muchova, and she was eliminated in the first round of Wimbledon by Kostyuk.

The upset thwarted an all-Top 10 Round of 16 clash between Sakkari and Muchova. This season, Muchova has already defeated Sakkari twice.

Karolina Muchova had the first main draw win of the US Open

The first winner of the 2023 US Open was No.10 seed Muchova of the Czech Republic. The new Top 10 member needed only 65 minutes to defeat Australian wild card Storm Hunter 6-4, 6-0 and secure a second-round berth.

Muchova led by a break twice in the first set, but Hunter fought back on both occasions to tie the game at 4-4. Muchova then turned up the heat, winning eight games in a row to claim her first US Open victory since a career-high run to the Round of 16 in 2020.

At this time last year, Muchova had dropped from the Top 20 to No.235, and she had lost in the first round of the 2022 US Open to eventual quarterfinalist Ajla Tomljanovic.

The Czech has had a meteoric rise since then, reaching her first Grand Slam final at Roland Garros in 2023 and her first WTA 1000 final earlier this month in Cincinnati. Following her run in Cincinnati two weeks ago, Muchova clinched her Top 10 debut.

Muchova will play Magdalena Frech of Poland in the second round.

SportsLigue