The match lasted just under 90 minutes, with the world number three Pole dominant throughout.
It was the fourth meeting between the two players, and Świątek's third victory over Osaka, who is currently coached by Tomasz Wiktorowski – the same man who guided the Polish player between 2021 and 2024.
Świątek has won the Rome tournament three times – in 2021, 2022 and 2024.
She is the only Polish woman remaining in the singles draw, after Magdalena Fręch and Magda Linette both fell in the first round.
The Polish player will next face American Jessica Pegula, the world number five, who defeated Austria's Anastasia Potapova 7-6 (8-6), 6-2 in the last 16.
(ał)
Source: PAP