Novak Djokovic kicked off his quest for a sixth Italian Open title and the defence of his world number one ranking with a 6-3, 6-2 victory over Aslan Karatsev in the second round on Tuesday.
Top seed Djokovic, who received a bye into the second round, is still seeking his first title of the year.
If Djokovic does not reach the semi-finals in Rome, he will surrender top spot in the rankings to Russian Daniil Medvedev for a second time this year.
The Serb, however, got the job done against Karatsev, who had beaten him in Belgrade last year.
"He's a very strong guy, just solid from the baseline. You never know with him. If he's feeling the ball, it can be very dangerous because he stays so close to the line and puts pressure on his opponents," Djokovic said.
"He was missing a lot of balls today though. He gave me a couple of breaks... I'll take this win, it's a straight sets win against a quality opponent."
Djokovic brought the crowd to its feet at one point, sprinting from one end of the court to the other, scrambling and sliding to reach for an outrageous drop shot at the net before opening up the court for a winner.
"Obviously that's what the crowd is looking for -- energy, excitement, they're looking for fight. They want to see some good tennis," the 34-year-old said with a smile.
"We had some nice points today. It's always great to play in the Colosseum of tennis."
Earlier, 2020 runner-up Diego Schwartzman saved two match points to edge Miomir Kecmanovic 6-2, 3-6, 7-6(3) to move into the second round while David Goffin upset 11th seed Hubert Hurkacz 7-6(8), 7-6(2).
Raducanu retires in Rome as back injury persists, Jabeur survives early scare
Briton Emma Raducanu was unable to overcome a back injury which forced her to retire from her first round match against Bianca Andreescu at the Italian Open on Tuesday.
Raducanu, who had also struggled with a back injury during her previous tournament in Madrid and a hip injury earlier this year, was trailing 6-2, 2-1 when she called it quits.
"Definitely disappointed with how today went. But I guess I wanted to give it a try. I never really knew how bad it was until I kind of went out there," Raducanu told reporters.
"I'm still learning when it's right to push my body and push through it, and when it's not. I guess that's something I'm learning at these tournaments.
"After Madrid I thought that maybe taking one, two days off, it would just go away because a lot of the other small niggles I've had, they've kind of gone away after taking two days off."
The battle of the reigning and former US Open champions on clay looked an intriguing prospect but Raducanu struggled from the outset and served poorly, handing Andreescu a number of break points.
Raducanu was clutching her back when she took a medical timeout after going 5-2 down but returned to the court minutes later where the Canadian held to love to take the opening set.
The 19-year-old Raducanu held serve at the start of the second set but looked uncomfortable yet again and this time she took the decision to retire when she was down 2-1 in the second.
Raducanu, who played on clay professionally for the first time last month, said she did not want to make a hasty decision to skip the French Open and focus on the grasscourt swing and her home Grand Slam at Wimbledon.
"Obviously I would not want to miss the French Open. The whole clay season leads up to it," she said.
"I think the last few weeks have been really positive. I've learnt a lot about myself and my game has definitely improved on this surface."
Tunisian Ons Jabeur, who became the first African player to win a WTA 1000 title in Madrid over the weekend, survived a second set wobble to dispatch Romania's Sorana Cirstea 6-0 7-6(1).
Jabeur looked set for a comfortable victory when she bagelled Cirstea and was 5-2 up in the second with 45 minutes played.
However, Cirstea fought back valiantly as Jabeur lost her focus and made a slew of errors, forcing a tiebreak where the Tunisian eventually prevailed to win her seventh consecutive match for the first time in her career.