The world number one easily won his 25th straight match, taking just over an hour to see off Australia’s Popyrin and set up an Italian derby with Andrea Pellegrino in the next round.
Pellegrino, 29, who beat 20th seed Frances Tiafoe 7-6 (10/8), 6-1, is a qualifier ranked 155 in the world who before this week had never played in the main draw of a Masters 1000 tournament.
“It’s fun to play a derby in Italy, he’s having an incredible tournament with a lot of victories against some really good oppoonents,” Sinner told reporters.
“We’ve played each other a long time ago (in 2019 in an ITF tournament), but he was a different player, and I was a different player.”
Sinner meanwhile is trying to extend his own record-breaking run of overall victories in the ATP’s top-ranked events after having won his last five.
The 24-year-old joins Novak Djokovic as the only player to win a year’s first 25 Master 1000 matches, with the Serbian tennis icon’s record run stretching to 31 matches in 2011.
Popyrin was suffocated by Sinner and made 23 unforced errors on his way to a comprehensive defeat.
The world number 60 only got 48 percent of first serves into play and that allowed Sinner to break five times and close out a match which was barely a contest.
“He’s a big server so his percentage was not very high, which helped me for sure a little bit, but I’ve been returning very well the second serves,” said Sinner.
Should Sinner prevail at the Foro Italico he will be the first Italian to win there since Adriano Panatta 50 years ago, and would complete his collection of Master 1000 tournaments.
With great rival Carlos Alcaraz out injured and Novak Djokovic eliminated early, Sinner will be red-hot favourite as he builds towards completing the career Grand Slam at the French Open which starts next week.
Former Rome champion Daniil Medvedev gets his tournament underway against Pablo Llamas Ruiz after a second-round walkover gave the Russian seventh seed automatic passage into the third. (AFP)