Maria Sharapova was sent tumbling out of Rome by Ana Ivanovic, who trounced the Russian 6-1 6-4 in the third round.
The Serbian 11th seed beat Sharapova, seeded eighth, for the first time in seven years with a blistering display of power to reach her sixth quarter final of 2014.
Ivanovic will face Carla Suarez Navarro in the semis after the Spaniard was granted a walkover against fourth-seeded Romanian Simona Halep, who pulled out with an abdominal strain.
The last time Ivanovic, 26, beat the Russian was in the semi-finals of the 2007 French Open. She went on to lose the final to Justine Henin.
Italian Open third round results
11-Ana Ivanovic (Serbia) beat 8-Maria Sharapova (Russia) 6-1 6-4
3-Agnieszka Radwanska (Poland) beat Francesca Schiavone (Italy) 6-4 6-1 1
0-Sara Errani (Italy) beat Petra Cetkovska (Czech Republic) 6-4 7-6(3)
2-Li Na (China) beat Samantha Stosur (Australia) 6-3 6-1
13-Carla Suarez Navarro (Spain) beat 4-Simona Halep (Romania) walkover
