Jannik Sinner booked a second-round showdown with nine-time champion Rafael Nadal at the Italian Open after a 6-2, 6-4 win over Frenchman Ugo Humbert on Monday.

The Italian teenager will face the 20-time Grand Slam winner for the second time, having impressed against Nadal in last year's French Open quarter-finals despite losing in straight sets.

Nadal has a 9-2 record on clay this season but was beaten in the last eight at both previous Masters events, in Monte Carlo and Madrid. 

Aslan Karatsev matched Sinner with his 20th win of the season. The Russian beat Miomir Kecmanovic 7-6 (7/2), 6-4 in the opening round. Only Stefanos Tsitsipas and Andrey Rublev have won more ATP matches this year (27).

Australian Open semi-finalist Karatsev will play compatriot and Melbourne runner-up Daniil Medvedev for a place in the last 16. Medvedev, who had a first-round bye, is chasing a first win in Rome in his third appearance at the tournament.

Taylor Fritz awaits defending champion Novak Djokovic in round two after the American brushed aside Dan Evans 6-3, 6-2. Djokovic and Nadal have accounted for 14 of the past 16 titles at the Foro Italico.

Kei Nishikori overcame Fabio Fognini 6-3, 6-4 in a meeting of former top-10 players.

Reigning women's French Open champion Iga Swiatek advanced when Alison Riske retired in the first set of their opening-round encounter, while Coco Gauff outlasted Yulia Putintseva 7-5, 4-6, 6-4.

Petra Kvitova recovered from a dreadful start to overhaul Magda Linette of Poland 1-6, 6-0, 6-2.