Moving on: Jannik Sinner on his way to victory over Alex Michelsen
Moving on: Jannik Sinner on his way to victory over Alex Michelsen AFP

Jannik Sinner won his 50th match of the year on Thursday to reach the US Open third round as 2022 champion Iga Swiatek stormed through, setting the scene for Carlos Alcaraz and Naomi Osaka to take night-time centre stage.

World number one Sinner defeated America's 49th-ranked Alex Michelsen 6-4, 6-0, 6-2 to make the last 32 in New York for a fourth successive year.

The 23-year-old Italian had already defeated his Californian rival just two weeks ago in Cincinnati and he repeated that outcome for his 30th hard court victory of 2024.

Sinner unleashed 28 winners and broke serve eight times.

"He's a very tough opponent. We played each other in Cincinnati. I knew what to expect, he knew what to expect a little," said Sinner.

Sinner went on to claim his fifth title of the season in Cincinnati.

A day later it was revealed that Sinner had escaped a ban despite twice testing positive for an anabolic agent in March, authorities accepting his explanation that the result was the result of contamination.

He will face Australia's Christopher O'Connell for a place in the last 16.

Swiatek charged into the third round, routing 217th-ranked Ena Shibahara of Japan 6-0, 6-1 to record her 55th match win of the year.

Poland's Swiatek, the 2022 US Open winner who is seeking to add a second title in New York to her four French Open triumphs, overwhelmed the 26-year-old qualifier, who was in the main draw of a Grand Slam for the first time, in just 65 minutes.

She committed only six unforced errors and goes on to face either 25th seed Anastasia Pavlyuchenkova or Elisabetta Cocciaretto.

Swiatek then saw likely semi-final opponent Elena Rybakina withdraw from the tournament ahead of her second round clash with 143rd-ranked French qualifier Jessika Ponchet.

There was no immediate indication as to why the fourth-ranked Russian-born Kazakh had pulled out.

Alcaraz, the 2022 champion, is seeded to meet Sinner in the semi-finals and is bidding to become just the third man in the modern era to win the French Open, Wimbledon and US Open in the same year.

The charismatic 21-year-old Spaniard takes on former quarter-finalist Botic van de Zandschulp having already beaten the 74th-ranked Dutchman without dropping a set in their previous two encounters.

Fellow crowd-pleaser Naomi Osaka, the 2018 and 2020 champion, plays 2023 semi-finalist Karolina Muchova of the Czech Republic.

Four-time major winner Osaka missed last year's tournament after giving birth to daughter Shai but she made up for that absence in the first round.

The Japanese star brushed aside former French Open winner Jelena Ostapenko with a dazzling display to match her show-stopping outfit.

Osaka appeared on court wearing a giant green bow on the back of her jacket, a tutu and small bows tied to the heels of her shoes.

For Thursday night's clash with Muchova, she is expected to wear a darker version of the same ensemble.

"A player came up to me and asked to take a picture. I hope it was a positive picture, it wasn't, like, Oh, my God, look at her," said Osaka on the reaction to her bright green colour scheme.

In early action, 2016 runner-up Karolina Pliskova suffered a left ankle injury and was forced to retire from her match with fifth-seed Jasmine Paolini after just three points.

"I hope she recovers soon because it's sad to see her leave the court like this. We didn't really play a match," said French Open and Wimbledon runner-up Paolini.

Polish seventh seed Hubert Hurkacz became the highest ranked man to fall when he lost in straights sets to Australia's Jordan Thompson.

US 16th seed Sebastian Korda was also eliminated in straight sets at the hands of Tomas Machac of the Czech Republic.

Also in action on the fourth day is 2021 champion Daniil Medvedev who tackles Hungary's Fabian Marozsan.

All over: Karolina Pliskova suffered an ankle injury and retired from her match with Jasmine Paolini after just three points
All over: Karolina Pliskova suffered an ankle injury and retired from her match with Jasmine Paolini after just three points AFP
Easy does it: Iga Swiatek celebrates after defeating Ena Shibahara of Japan
Easy does it: Iga Swiatek celebrates after defeating Ena Shibahara of Japan AFP