ROME, Italy (AFP) — Jannik Sinner got his Italian Open campaign underway by swatting aside Sebastian Ofner 6-3, 6-4 to start his bid to extend a record-breaking run of five straight Masters 1000 tournament victories.

The world No. 1 delighted fans in the packed center court stands with a predictably dominant display, which left Austria's Ofner little room to breathe, even in the breezy atmosphere of Rome.

Sinner won his 24th consecutive match in one hour and 40 minutes, the 24-year-old barely breaking a sweat to set up a clash with Alexei Popyrin or Jakub Mensik in the third round.

No Italian man has won at the Foro Italico since Adriano Panatta 50 years ago, and with Carlos Alcaraz out of action, Sinner is expected to go one better than last year when he lost the final to his great rival.

Such was Sinner's dominance that he had time to break into a smile when the match was stopped twice in the second set for spectator illnesses.

"I'm very happy to be back here, it's always been a very special tournament for me," Sinner said.

"I'm trying to get into a good match rhythm again, even though I've played a lot in the last couple of months... I'm very happy and now let's see what's coming also in the next round."

It was the third win for an Italian man on Saturday, with Flavio Cobolli, who helped his country win last year's Davis Cup in Sinner's absence, beating France's Terence Atmane 7-6 (7/1), 6-3.

Mattia Bellucci, ranked 64 in the world, is in the fourth round after a 5-7, 6-2, 6-3 win over 24th seed Tomas Martin Etcheverry.

Former winner Daniil Medvedev will begin his campaign in the third round after his match, which was scheduled to be the first on centre court, was shelved when his opponent Tomas Machac pulled out of the tournament with an unspecified illness.

Fourth seed Felix Auger-Aliassime suffered a shock second-round defeat at the hands of Argentina's Mariano Navone, the Canadian losing to his 44th-ranked opponent in straight sets 7-6 (7/4), 7-6 (7/5).

Women's world No. 1 and favorite for overall victory, Aryna Sabalenka followed men's tennis icon Novak Djokovic in going out early following a 2-6, 6-3, 7-5 loss to Sorana Cirstea.

Sabalenka was visibly frustrated with her performance on centre court, muttering to herself with her shoulders slumped during an uncharacteristically sloppy display.

"I feel like I didn't play well from the beginning till the end. I started really well, but then I kind of dropped the level," Sabalenka said.

"Felt like my body was limiting me from performing on the highest level."

The 28-year-old had not been knocked out of a tournament in the Round of 32 since the Qatar Open in February last year, and she looked set for a quick and clean victory after racing to the first set.

But she failed in her bid for a first tournament victory in the Italian capital, with Romania's Cirstea facing Linda Noskova in the next round after beating a woman at the top of the world rankings for the first time in her career.