NEW YORK -- Jannik Sinner surged into the third round of the US Open on Thursday, beating Alex Michelsen 6-4, 6-0, 6-2 in 1 hour, 39 minutes.
The No. 1-ranked Sinner dropped the first set in his opening match in New York but didn't encounter much trouble facing his second straight American on Arthur Ashe Stadium. The Italian earned his 50th victory of the season, including his ATP Tour-leading 30th on hard courts.
His previous one was a little shaky after a slow start against Mackie McDonald, so Sinner got in a practice session after that match and was happy with the results Thursday.
"Trying to keep going, trying to understand what works here best on these courts," he said. "Let's see what I can do in the next round."
That will be against Christopher O'Connell of Australia on Saturday.
Sinner beat Michelsen for the second time this month, having also won a second-round match in Cincinnati shortly before it was revealed that he tested positive twice for an anabolic steroid in March.
"Very happy to be through against a very tough opponent," Sinner said. "We played each other in Cincinnati ... so I knew a little bit what to expect. I think also he knew a little bit what to expect."
No. 5 seed Daniil Medvedev breezed past Hungary's Fabian Marozsan 6-3, 6-2, 7-6 (5). The 2021 US Open champion will face 31st seed Flavio Cobolli of Italy in the third round.
Medvedev, helped by his opponent's 45 unforced errors and poorly-timed drop shots, sealed victory with a leaping backhand on match point and afterwards appeared annoyed with the muted reaction from fans at Flushing Meadows.
"The match today, I felt like I was at an Italian restaurant ... it was so noisy," Medvedev said in an on-court interview at Louis Armstrong Stadium. "Unless Roger [Federer] or the home favorite is playing, whoever is losing gets a little more support. [Marozsan] started playing really well in the third set, so the crowd went behind him.
"So every time I would win some important point, I was like, 'Cme on, give me a little bit.' It was really fun."
In other men's singles results from Thursday, No. 7 seed Hubert Hurkacz was eliminated in straight sets by Australia's Jordan Thompson, the sixth straight year Hurkacz has lost in the second round at Flushing Meadows.
Thompson faces Italian 30th seed Matteo Arnaldi in the third round.
No. 16 Sebastian Korda, who struggled throughout with a right elbow injury, was knocked out by mixed doubles Olympic gold medalist Tomas Machac 6-4, 6-2, 6-4.
Nuno Borges defeated Thanasi Kokkinakis 6-4, 7-5, 7-5 to become the second Portuguese man in the Open era to reach the third round in New York, joining João Sousa who reached that stage three times (2013, 2016 and 2018).
No. 10 Alex de Minaur needed a third-set tiebreak but got past Finland's Otto Virtanen 7-5, 6-1, 7-6 (3).
"I'm happy to keep going every day, I'm getting a little bit better and I'm looking forward to what's to come," said De Minaur, who is playing his first tournament since pulling out of Wimbledon because of a hip injury. "Still not a lot of expectations, but I know every time I step out there, I'm going to compete, I'm going to try my hardest and hopefully put on a show."
With De Minaur's win, Australia now has four men (O'Connell, Thompson and Alexei Popyrin are the others) through to the third round, the country's most at a US Open since 1997. Patrick Rafter, Mark Philippoussis, Mark Woodforde and Scott Draper all reached the third round in New York in 1997, with Rafter going on to win the title.
Max Purcell was unable to join his Australian compatriots in Round 3 when he retired in the third set against Tommy Paul with the American 14th seed leading 7-5, 6-0, 1-0.
It was hardly the way Paul wanted to advance, but the early night was perhaps a welcome relief after his first-round affair against Italian Lorenzo Sonego went well past 1:00 a.m. ET.
"I was playing really well but it's unfortunate," Paul said. "I thought I picked up my serve there in the second set, I started hitting my forehand really well."
Paul will face Gabriel Diallo in the third round after the Canadian topped France's Arthur Fils 7-5, 6-7 (3), 6-4, 6-4.
Jakub Mensik staved off two match points and came back from two sets down against Tristan Schoolkate to reach the third round for a second straight year.
After playing a marathon 5:35 first-round match against Karen Khachanov -- the longest ever at the US Open -- Daniel Evans extended his New York stay with a straight-sets win over Mariano Navone.
ESPN Stats & Information, The Associated Press and Reuters contributed to this report.