World No 3 Jessica Pegula is out of the Rome Masters after falling to a shock defeat against Taylor Townsend on Thursday.
American Townsend is through to the third round at a WTA 1000 event for only the second round time in her career after beating her countrywoman 6-2, 3-6, 6-3.
Townsend's only previous victory against a top-10 player came during a breakthrough fourth-round run at the 2019 US Open, where she beat then-No 4 Simona Halep in the second round inside Arthur Ashe Stadium.
She will now face China's Wang Xiyu who defeated Madrid Masters quarter-finalist Irina-Camelia Begu of Romania 6-4, 7-5.
Victoria Azarenka stepped up her singles game in Rome after defeating Sloane Stephens 6-4, 6-3 at Foro Italico.
Fresh from winning a doubles title alongside Beatriz Haddad Maia in Madrid last week, Azarenka started her campaign in Italy with victory over the American who was coming off a singles victory at a smaller clay-court event in Saint Malo, France.
Despite the score line, Azarenka's one hour, 42-minute victory was far from straightforward. The 2013 finalist trailed by a break twice in the first set and once in the second; there were 10 breaks of serve in total.
“I was definitely quite nervous before the match,” said Azarenka, who will now take on another American in Madison Keys.
“I felt like I didn’t have too many matches under my belt and Sloane just won the tournament, so I knew she’s in a good form, so I just tried to kind of stay focused on myself.”
Azarenka is making her 14th appearance at the Foro Italico, having reached the final in 2013, when she lost to Serena Williams.
“It feels like it was such a long time ago,” Azarenka added. “Time goes by fast. I try to appreciate every moment I have on the court. I’m not sure how long I will play longer, so I want to enjoy it. But I still feel like I can be very competitive.”
Last year's French Open runner-up, Coco Gauff, routed Yulia Putintseva 6-0, 6-1 on way to a 59-minute victory.
“I usually have long matches with her. I was fully prepared for that. But I told myself to play on my terms, not her terms,” said the 19-year-old American who is seeded sixth.
“She’s obviously a tricky player, has some big wins. Made the quarters of the French a couple times. I know clay is her surface. It’s also kind of mine, too, so it was a good match today.”
Gauff will face 27th seed Marie Bouzkova next for a spot in the last 16. The Czech rallied from 4-0 down to Caty McNally of the US to win 10 consecutive games before closing out a 6-4, 6-3 win.
Czech Republic's Karolina Pliskova, the 2019 Rome champion and two-time runner-up, was eliminated by Hungarian qualifier Anna Bondar 7-6, 6-2.