Two of the world's top three were knocked out of the second round of the Italian Open by players outside the world's top 100 on Thursday.
Belarusian Aryna Sabalenka, the world number two and Australian Open champion, was upset 7-6 (7-4) 6-2 by Sofia Kenin of the US, ranked 134.
Meanwhile, third seed Jessica Pegula lost 6-2 3-6 6-3 to fellow American Taylor Townsend, currently ranked 168.
Compatriot Coco Gauff and Belarusian Victoria Azarenka managed to progress.
Gauff continued her preparations for the French Open by dropping only one game in her victory over Kazakhstan's Yulia Putintseva.
Last year's French Open runner-up, 19, needed one hour exactly to claim a 6-0 6-1 win in Rome.
World number 17 Azarenka earned a 6-4 6-3 victory over American Sloane Stephens, who won in Saint-Malo last week.
Sabalenka, 25, had reached the final of her last two tournaments, beating world number one Iga Swiatek to win the Madrid Open last week.
But she was upset by former world number four Kenin, who has slipped down the rankings since winning the 2020 Australian Open and registered her first win in Rome since 2019.
It was also the 24-year-old's first victory against a top-10 opponent since shocking then-world number one Ashleigh Barty in the semi-finals as she advanced to her solitary Grand Slam triumph in Melbourne.
