Iga Swiatek produced a statement victory in a battle between two of the game’s best, mercilessly dismantling Naomi Osaka 6-2, 6-1 to return to the quarter-finals of the Italian Open.

This was the type of confidence-building performance Swiatek, the fourth seed, has been seeking for some time. After a tense opening four games, the four-time French Open champion put together a near flawless match, winning 10 of the last 11 games. Swiatek found a sweet balance between stifling Osaka with her heavy topspin and offensive weaponry while also drawing errors from her adversary with her tireless consistency.

In a match that pitted the six-time grand slam champion Swiatek versus the four-time major champion Osaka, this was by far the most eye-catching meeting of the tournament so far. Considering the level Osaka displayed in her performance against the 19th seed Diana Shnaider in the previous round and, in their instant classic French Open second-round match two years ago, which Swiatek won after facing match point, Osaka entered BNP Paribas Arena with reason to believe that she could at least make Swiatek uncomfortable.

However, a near-perfect serving day was required from Osaka just to stand a chance. Her poor serving performance from the beginning set the tone for a quick, painful evening. In cold, heavy and slow night time conditions, her attempts to play fast-paced first-strike tennis quickly came undone against one of the best defensive players on the tour as errors piled up.

The past few months have been a steep learning curve for Swiatek, her poor results leading to a split with her coach, Wim Fissette, in favour of hiring Francisco Roig in March. After some time spent training at the Rafa Nadal Academy, including a couple of training sessions with Nadal himself, their first big tournament together at the Madrid Open two weeks ago ended prematurely as Swiatek was forced to retire from her third-round match against Ann Li due to illness. Swiatek is a three-time champion in Rome, her most successful event outside of Roland Garros, and in these familiar stadiums she took a significant step towards regaining her top form. Swiatek will next face the in-form fifth seed Jessica Pegula.

However, it is fair to say that the partnership between Swiatek and Roig started on the wrong foot. A few days before the tournament, Swiatek was training on the tournament’s clay court built inside Piazza del Popolo, a famous square in Rome, when Roig tore his achilles during a volley game they were playing. “We made a bet for €100,” said Swiatek. I thought I was going to lose, honestly, because he plays the volley so great. I was like: ‘Maybe let’s play only the singles court.’ It’s half-court basically. [But then] ‘Let’s play doubles. I want to win, I’ll make you move a little bit.’ I had 5-4 and the match point already. He did a split step and tore his achilles.”

Roig was rushed to Warsaw with Swiatek’s psychologist, Daria Abramowicz, where he underwent surgery. Within days, he was back in Rome with the Swiatek team while navigating the vast tournament grounds on crutches. “Yeah, I broke my coach’s achilles …” Swiatek said meekly.

Elsewhere, Jannik Sinner continued to bulldoze all opponents in his path as he secured a 30th consecutive Masters 1000 win by beating Australia’s Alexei Popyrin 6-2, 6-0 to ease into the fourth round. Sinner, a finalist in Rome last year, is attempting to win a record-extending sixth consecutive Masters 1000 title. He will next face his fellow countryman, Andrea Pellegrino.

Things were far less straightforward for Coco Gauff, the third seed and last year’s finalist, who saved a match point against the 16th-seeded American Iva Jovic while trailing 5-7, 3-5 before recovering to reach the quarter-final with a gritty 5-7, 7-5, 6-2 win. Gauff disclosed earlier in the tournament that she has been dealing with some personal issues away, which has at times made it challenging for her to find sufficient motivation on the court, but she continues to fight through.

“I wasn’t really proud of the way I showed up in my last match,” said Gauff. “Today I was like, I’m not going to be like that. I thought I did a good job. Obviously, there’s moments I did get negative. I’m not perfect.

“I’m a work in progress. Today for the most part I was really mentally sound. I think that’s something to be proud of and be able to try to remember the next time I’m in a moment like that.”