Defending champion Elina Svitolina recovered from a love set to beat Daria Kasatkina and reach the quarter-finals of the Internazionali BNL d'Italia.
The fourth seed won only seven points in the opening set against her young Russian opponent but worked her way into the match and eventually prevailed 0-6 6-3 6-2 to set up a clash with 11th seed Angelique Kerber, who defeated Maria Sakkari 6-1 6-1.
Top seed Simona Halep, the runner-up to Svitolina 12 months ago, did not even have to take to the court to book her spot in the last eight after opponent Madison Keys pulled out with a rib problem.
Reaching the quarter-finals means Halep will hang onto her world number one ranking if she progresses further in the tournament than Caroline Wozniacki, who was due to face Anastasija Sevastova later on Thursday.
For the second week in a row, Estonian Anett Kontaveit knocked out Venus Williams, the clay lover following up her victory in Madrid with a 6-2 7-6 (7/3) win.
French Open champion Jelena Ostapenko also made it through to the last eight, making it an unhappy 27th birthday for Johanna Konta by recovering from a set down to win 2-6 6-3 6-4.