China's Shuai Peng struggled during the US Opens semifinals game against Caroline Wozniacki. Peng frequently clutches her left thigh using her racket as a cane to support her body.

Peng tried hard to continue the game but eventually, her body gave in that she dropped her racket and grabbed at her right knee, then staggered toward the wall behind the baseline and leaned against it.

She wiped her tears away as a trainer came towards her. After the trainer were a doctor, the chair umpire, a tournament official, a security guard, a ball kid with an umbrella to offer shelter from the sun.

Clearly in pain, Peng limped her way to the hallway adjacent to the court where she was diagnosed with heat illness which needed treatment. The game was delayed for almost 10 minutes in which right after, Peng went back to the court and play. As much as she tried, the pain was more than she could bear as she finally couldn't take it and she falls to the ground. Wozniacki looked on clearly concerned for her opponent's health but was unable to do anything. Peng stopped while trailing 7-6 (1), 4-3, allowing Denmark's Wozniacki to reach her second Grand Slam final.

Four hours after the game at a news conference, Peng told reporters that she was feeling better and was not sure whether it was her or the doctors who decided to end the game but she recalls how she reacted when the doctors suggested to end it.

She said "'I said, 'No, no, no. I don't want to give up. I want to try one more time. I knew I'm not going to stay maybe too long, but I just want to try, you know. I just wanted to challenge her one more time."

According to 10th-seeded Wozniacki "'It was really hard to watch. To see her struggling out there - I just wanted to make sure she was OK."

This coming finals on Sunday, Wozniacki will then face her good friend, Serena Williams. Williams defeated 17th-seeded Ekaterina Makarova of Russia 6-1, 6-3 to extend her U.S. Open winning streak to 20 matches.