World number one Sinner continued his Foro Italico comeback from a three-month doping ban by dealing with lucky loser Jesper de Jong 6-4, 6-2 and setting up a clash with Argentina’s Francisco Cerundolo on Tuesday.
Sinner was knocked out in the last 16 by Cerundolo the last time he played here, in 2023, and he is under no illusions that the 17th seed will be a big step up after low-ranked opponents in his first two matches.
“Tomorrow will be a big day for me, because I’ll need to raise my game against him,” Sinner said.
“He’s played some really good tennis recently, he got to the semi-finals in Madrid and he’s playing some real tennis. He’ll be confident.”
The over 10,000 fans crammed into the centre court stands hoped Sinner can end a 49-year wait for an Italian winner of the men’s tournament in the capital.
Monday’s win was in reality another warm-up for the 23-year-old’s stated objective of arriving at the French Open in top form.
Sinner’s compatriot Jasmine Paolini cruised past Jelena Ostapenko and into the women’s quarter-finals, easing past her Latvian opponent in straight sets 7-5, 6-2.
Fellow Italian Matteo Berrettini made a tearful exit as he retired with an abdominal problem while trailing sixth seed Casper Ruud 7-5, 2-0 in their clash.
Ruud next plays 66th-ranked Spaniard Jaume Munar for a place in the quarter-finals, where he could face Sinner.
Sabalenka again had to fight to beat Kostyuk 6-1, 7-6 (10/8) in the day’s final match, taking just half an hour to win the first set but then being truly tested before sealing a spot in the women’s last eight.
“I’m just thrilled with the performance today, I really enjoyed this fight and super happy to get this win,” she said.
Kostyuk engaged Sabalenka in a series of exciting rallies and pushed Sabalenka, with the 20-point game seven of the second set a particular high point of their battle.
World number one Sabalenka has reached the final of her last four tournaments, winning in both Miami and Madrid, and is favourite at the Foro Italico following the early elimination of reigning champion Iga Swiatek on Saturday.
Sabalenka will face eighth seed Qinwen Zheng next with a third 1000 series crown of the season just before the tennis world decamps to Paris for the second Grand Slam of the year.
Coco Gauff could be Sabalenka’s opponent in the semi-finals after the American made short work of Emma Raducanu, winning 6-1, 6-2 in just over an hour to reach the last eight where Mirra Andreeva awaits.
Naomi Osaka’s struggle for form at the top level continued with her 6-4, 3-6, 7-6 (7/4) defeat to Peyton Stearns.
In the quarter-finals Stearns will face Elina Svitolina, a 6-4, 6-2 winner over Danielle Collins, after coming through an attritional match which lasted the best part of three hours on a baking centre court. (AFP)