China tennis star Zheng Qinwen was described as a "cut-throat" by her beaten Olympic Games opponent on Tuesday.
World No 7 Zheng saved a match point to defeat Emma Navarro of the United States 6-7 (7/9), 7-6 (7/4), 6-1 to reach the quarterfinals.
However, tempers boiled over after a three-hour match in which Zheng had also fought back from trailing 3-5 in the second set.
"I just told her I didn't respect her as a competitor," said Navarro on the pair's heated exchange at the net.
"I think she goes about things in a pretty cut-throat way. It makes for a locker room that doesn't have a lot of camaraderie, so it's tough to face an opponent like that, who I really don't respect.
"But, kudos to her, she played some good tennis there at the end. She played better than me, so congrats to her."
Zheng, roared on by Chinese fans who packed out Court Seven, braving temperatures which soared to the mid-30s, said Navarro was a "great opponent".
"She told me she doesn't know how I have a lot of fans," said Zheng, who enjoyed a breakout run at the Australian Open in January when she made the final.
"It looks like she's not happy with my behaviour towards her. If she's not happy about my behaviour, she can come and tell me. I would like to correct it to become a better player and a better person."
The 21-year-old added: "I'm glad that she told me that. I will not consider it an attack because she lost the match."
Zheng, one of two Chinese women to reach the last 16 of the singles, will face former world No 1 and three-time major winner Angelique Kerber for a place in the semifinals.
Kerber, 36 and playing in her final tournament before retirement, defeated Leylah Fernandez of Canada 6-4, 6-3.
"I'm just looking day by day, match by match, and just trying to enjoy it. I'm feeling good on court, and let's see how far I can get," said the German.