Victoria Azarenka showed her sporting prowess last week when she won the U.S. Open women's singles title.

On Friday in Rome, she showed her character.

The Belarusian star was playing a first-set tiebreaker in the Internazionali BNL d'Italia against Daria Kasatkina when the Russian player tripped and injured her right ankle.

As Kasatkina sat on the clay surface, Azarenka fetched an ice bag and brought it to her. Azarenka brought over a towel to dust clay off Kasatkina's legs. After Kasatkina went to the sideline and the match was halted, Azarenka consoled her as she sobbed, even packing her bag to assist.

"I'm really sad for Daria, because we were playing such great tennis. I felt that it was such a great fight," Azarenka told reporters after the match, which had eight breaks of serve.

"She's such a talented player that I felt like is always on the verge of kind of that breakthrough where she's going to pick it up. I felt like this was maybe closer to be her moment, so it's very unfortunate that she has an injury.

"I offered her my help and my team's help if she needs it. I really hope she recovers. She's been playing so beautifully, so smart on the court, putting me in very uncomfortable situations where I had to really push myself."

Due to Kasatkina's injury, Azarenka advances to the tournament's quarterfinals, where she will be joined by the tournament's top two seeds.

No. 1 Simona Halep of Romania defeated Ukraine's Dayana Yastremska 7-5, 6-4, and No. 2 Karolina Pliskova of the Czech Republic beat Russia's Anna Blinkova 6-4, 6-3.

Fourth-seeded Elina Svitolina of Ukraine also moved on, topping Russia's Svetlana Kuznetsova 7-6 (6), 6-4. No. 11 Elise Mertens of Belgium eliminated Montenegro's Danka Kovinic 6-4, 6-4, and No. 12 Marketa Vondrousova of the Czech Republic rallied past Slovenia's Polona Hercog 1-6, 6-1, 7-6 (5).

Hercog served for the match at 6-5 in the third set, but Vondrousova broke to level the score. In the decisive tiebreaker, after the server won each of the first two points, the return won the next nine consecutive points. When Vondrousova finally held serve again, she won the match.

Unseeded Garbine Muguruza of Spain, a two-time Grand Slam champion, defeated seventh-seeded Johanna Konta of Great Britain 6-4, 6-1. The only other seeded player to lose Friday was No. 10 Elena Rybakina of Russia, who fell 4-6, 7-6 (3), 6-2 to Kazakhstan's Yulia Putintseva.