NEW YORK, Aug. 29 (Xinhua) -- Chinese veteran player Peng Shuai lost to Maria Sakkari of Greece in three sets in the second round of the ongoing US Open here on Thursday.

Peng, who had an operation on her right knee in February, battled two hours and 40 minutes before losing at 6-7(5), 6-4, 6-2.

The first set was hotly contested, with Peng and Sakkari exchanging breaks in early stage. Then both players played solid game in respective serve until the set was forced into the tiebreak. Peng raised up her level in time before securing the tiebreak at 7-5.

However, the 33-year-old Peng looked rusty and seemed to run out of steam in the second and third sets, losing at 6-4 and 6-2 respectively.

"I think I had ups and downs in the second set and then I felt tired. My opponent is really strong and I think she is able to play a five-set match. In spite of the loss, I still feel that I can play my game, and it really gives me confidence," Peng said.

"I started to talk a lot about the retirement after my operation, and many people said I should give it another try. But it's hard for me to get to the peak again. I just try to relax and enjoy the sport. I'm happy that I can still play," added Peng, currently ranked 167th in the world.

Peng will team up with Poland's Alicja Rosolska to play the women's doubles event at the US Open.

"I will try my best to raise up my rankings in doubles event and hopefully I can make the doubles event in next year's Tokyo Olympics," she added.