Playing the last match of the day, Sinner made quick work of his opponent. He dominated all three sets, didn't drop serve, and defeated Musetti for the third consecutive time. In total, Sinner has beaten his fellow Italians in all 16 of their encounters since joining the ATP Tour.

Musetti’s playing style is similar to Sinner’s, but at a lower level. His one-handed backhand proved less consistent than the world number one’s. He frequently lost in baseline rallies. Volleying and net play are not Musetti’s strengths, making it difficult for him to disrupt Sinner’s rhythm. In all three sets, the 10th seed lost serve early and couldn't recover, despite having seven break points.

Sinner hits a backhand in the US Open quarterfinals at Arthur Ashe Stadium, New York, on 4/9. Photo: Reuters

Sinner hits a backhand in the US Open quarterfinals at Arthur Ashe Stadium, New York, on 4/9. Photo: Reuters

"Musetti and I know each other very well, and we're also friends," Sinner said after the match. "But both of us have to put friendship aside when we face each other on the court. I'm happy that we and other Italian players are meeting more often in major tournaments."

Sinner’s performance was deemed flawless by the ATP, similar to his fourth-round victory over Alexander Bublik, where he conceded only three games. Sinner becomes the second-youngest player in the Open Era to reach the semifinals of all four Grand Slams in a single year, following Rafael Nadal, who achieved the feat at age 22 in 2008.

Sinner continues to defend his US Open title with a 26-match winning streak at hard-court Grand Slams – equaling the achievements of Novak Djokovic and Ivan Lendl. Djokovic also has a 27-match winning streak on hard courts at majors. Roger Federer holds the record with 40 consecutive wins from 2005-2008.

Sinner’s semifinal opponent is Felix Auger-Aliassime, who is on a hot streak. In the quarterfinals, the Canadian player came back from behind to beat Alex de Minaur 4-6, 7-6, 7-5, 7-6, after trailing 2-5 in the fourth set.

Sinner will retain the world number one ranking if he performs better than Carlos Alcaraz at the US Open. Many experts predict the two will meet again in the final, marking their third consecutive Grand Slam final clash, starting from Roland Garros. Last month, the pair met in the Cincinnati Masters final, where Sinner retired due to fatigue.

Vy Anh