Garbine Muguruza claimed a hugely encouraging win ahead of her French Open title defence, beating Venus Williams in three sets to reach the semi-finals of the Internazionali BNL d'Italia on Friday.
The champion at Roland Garros 12 months ago has struggled for form in 2017 and was thrashed 6-1 6-3 by Timea Bacsinszky in her first match at last week's Madrid Open.
However, Muguruza has looked a different player in Rome and produced a largely high-quality display to beat veteran Williams 6-2 3-6 6-2.
The Spaniard will face Elina Svitolina in the last four after the Ukrainian recorded a first career victory over second seed Karolina Pliskova.
Svitolina, who has beaten world number one Angelique Kerber three times this season, triumphed 6-2 7-6 (11-9) to end a run of four straight defeats against the Czech.
The other semi-final in Rome will see sixth seed Simona Halep face Kiki Bertens following their respective wins over Anett Kontaveit and Daria Gavrilova.
SECOND-SET LAPSE NOT COSTLY FOR MUGURUZA
Muguruza displayed fine form in the first and third sets against Williams, but lost her radar in the middle of the match - making 20 unforced errors during set two.
When Williams broke for a 1-0 lead in the decider, things looked bleak for Muguruza.
However, the 23-year-old hit back - aided by a host of errors from her opponent - to ultimately triumph with a degree of comfort.
IN-FORM HALEP EASES THROUGH
Halep made serene progress to the last four, continuing the Romanian's fine form.
Having claimed the Madrid Open title, which came hot on the heels of a semi-final spot in Stuttgart, Halep secured a dominant 6-2 6-4 triumph over Kontaveit.
The Estonian had stunned world number one Angelique Kerber in the second round, but found the fourth-ranked Halep a more difficult opponent.
Despite dropping serve once in each set, Halep always looked comfortable and is limbering up nicely for the French Open, where she reached the final in 2014.
She will now face Kiki Bertens, who beat Daria Gavrilova 6-3 6-3 to reach her first semi-final this year.
PLISKOVA UPBEAT DESPITE DEFEAT
Although Pliskova suffered defeat on Friday, she took heart from the fact her three victories in Rome this week more than doubled her number of clay-court wins in 2017.
"I would say I've had three good matches here, which is better than all the other tournaments where I was playing on clay," she said.
"It's definitely an improvement, and there's still Paris in front of me."