BEIJING, China -- No.9 seed Jelena Ostapenko of Latvia was on the court for a very short time in her third round match at the China Open on Thursday, as her opponent, China's top player Peng Shuai, unfortunately had to retire due to a knee injury while trailing 3-0.

The match between the two players was hotly anticipated, as Ostapenko, the reigning French Open champion and latest qualifier for the 2017 BNP Paribas WTA Finals Singapore presented by SC Global, was going to face off for the first time against the Chinese No.1 and World No.25.

But Peng could not overcome the lingering injury which had been plaguing her of late, and had to tap out after 15 minutes. "It’s not the result I wanted to have," Ostapenko told the press after the match. "Of course I feel bad for Shuai, and hopefully she can recover and will be fine."

"Maybe for me, it was a little advantage that I didn’t have to play the full match, as I was playing a lot of matches in the last couple of weeks, so I can rest a little bit more," Ostapenko continued. "I’m really happy to be in the quarters."

Ostapenko was in command of the match from the very beginning, using her outrageous groundstrokes to keep the heavily strapped Peng off balance. The Latvian quickly broke for a 1-0 lead off of a forehand crosscourt winner, and Peng already appeared to be struggling with her mobility.

After a quick hold for 2-0 by the French Open victor, Peng started to find the range on her serve, and held a game point for 2-1. But a scintillating backhand second serve return by Ostapenko erased that chance, and another bruising backhand return gave the Latvian a double-break lead on her third break point of the game.

Facing the 3-0 deficit, Peng called for the trainer to tend to her injury. After a quick consultation, the Chinese star deemed herself unable to continue, but she still leaves Beijing bettering her second round result from last year.

After the match, Peng told the press that her knee was "fine. But maybe recently there were ups and downs and several matches in a row that stressed it."

"After the season, I hope to stay in Germany for medical treatment and rest for a prolonged period," Peng elaborated. "The doctor suggested I should take a period of rest and get it treated, but I can only rest after the season. That's the plan." Peng also stated that she would continue to play in the doubles in Beijing.

Ostapenko, meanwhile, advances to the quarterfinals of the China Open for the first time in her career, where she will take on Sorana Cirstea, who dispatched No.4 seed Karolina Pliskova earlier on Thursday. Ostapenko beat Cirstea, her current doubles partner, in their only prior meeting, in the second round of this year's US Open.

"She’s a really nice girl and a great player, and I think we’re good friends now," Ostapenko said of Cirstea, after the match. "She plays similar to me, I think -- [Cirstea] plays aggressive tennis. And in New York we had some really good rallies, so hopefully tomorrow we will have a good match."