Maria Sharapova reached the quarterfinals of the Shenzhen Open on Wednesday after Chinese teenager Wang Xinyu retired in the second set with cramps.
Sharapova, who lost the first set 7-6 (4), was leading 5-2 in the second before the 17-year-old Wang was forced to quit.
"It's not the way either of us wants to finish the match, win or lose," Sharapova said. "I thought (Wang) was absolutely the dominant player in this match, and had all the opportunities to win it, even though I felt like I was finding my stride and getting a little bit closer to the line and being more aggressive."
Wang, who won two Grand Slam doubles titles last year, received a wild card into the Shenzhen event.
"She has all the tools to play well, and I think she showcased that, and it's obviously a very unfortunate way to end the match," Sharapova said.
Sharapova will next face top-seeded Aryna Sabalenka of Belarus in the quarterfinals. Sabalenka defeated Ekaterina Alexandrova of Russia 6-3, 6-3.
Earlier, Wang Yafan reached the quarterfinals by beating Ons Jabeur of Tunisia 3-6, 6-4, 6-4. She will next face Monica Niculescu of Romania, who defeated Kristyna Pliskova of Czech Republic 6-7 (2), 6-3, 6-4.