NEW YORK -- The final moments of the match were difficult. Peng Shuai, who had already been taken off the court for an injury assessment after cramping that rendered her nearly immobile, had returned to play five points in the U.S. Open semifinal against No. 10 Caroline Wozniacki.
"The doctor, she said to me, 'You are not able really go out to fight, compete, because look is not really well,'" Peng said. "I said, 'No, no, no, I don't want to give up. I want to try one more time.' Yeah. And then I come back ... I know I'm not gonna stay maybe too long, but I just want to try, you know. I just wanted to challenge her one more time."
But then, Peng collapsed again under the hot, mid-afternoon sun, pain etched on her face. Ultimately, the unseeded player retired from her match and left her first Grand Slam semifinal of her career sobbing in a wheelchair as Wozniacki joined a solemn standing ovation.
"I hope she'll be OK," Wozniacki said of Peng after the match ended.
USTA officials said Peng was indeed improving in the hours after the match ended.
Wozniacki reaches her first US Open final since 2009. The final score was 7-6 (1), 4-3 with Peng's retirement, the first semifinal retirement at the US Open in the Open era. The truth is it's a huge opportunity for Wozniacki, who has never won a Grand Slam title despite being the world's No.1 player for 67 weeks in 2010 and 2011.
"I have been close before, but, you know, it's obviously a Grand Slam final. I would love to win it and have a Grand Slam under my belt," Wozniacki said. "It would definitely have the media stop talking about my lack of a Grand Slam, so that would be nice."
There was confusion during the match about the amount of time that could be used to evaluate Peng's condition. US Open tournament director David Brewer said the trainers were able to use a "reasonable amount of time" to check Peng over.
"When we finish first set already maybe one hour or 50 minutes, and the heat is really hot. I just try to fight, and my body is getting more and more hot and it start cramping," Peng said. "It's really painful right there."
When she first limped to the wall behind the court, trainers came over, gave Peng a sports drink and helped her up and took her to the locker room for an injury evaluation. Brewer said Peng was diagnosed with "heat illness" and given three minutes of treatment -- the allotted time.
Had she been ruled to be cramping, much less help would have been available for Peng. The rules on that changed in 2010 over concerns that players were using medical timeouts for cramps as a way to gain a tactical advantage during crucial moments. Now, players can be treated for cramping only during changeovers or at the end of a set. To get treatment, a player must forfeit the points to get to the next changeover.
"If it's just cramping, then you can't have a medical, but whenever it's heat illness, then you're allowed to get treatment for it," Wozniacki said. "Honestly, I was just trying to focus on myself. I knew that it looked really bad out there, so I thought maybe she was still going to be OK to play afterwards."
It was hot -- the temperature on the court was in the high 80s -- but that wasn't the hottest conditions of the tournament. Still, when the wet bulb temperature is above 30.1 degrees Celsius, special heat rules are in effect. The temperature at 1 p.m. on Arthur Ashe Stadium was 30.9, or 87 degrees.
"Ladies and gentleman, for the moment Peng Shuai is receiving an evaluation," chair umpire Lousie Azemar Engzell said to the crowd.
So Wozniacki, who was facing a break point at 4-3, 30-40, pantomimed her service motion at the baseline as everyone waited.
"You know, I was just trying to focus on myself," Wozniacki said. "I was thinking that she was going to come out there and be ready to play, so I was doing a lot of serves. I was just training my serve down the T, because that was the one that I wanted to do on the first point."
As 10 minutes elapsed, CBS analyst Mary Carillo noted, "That is not a reasonable amount of time if you're Caroline Wozniacki."
At one point Wozniacki asked Engzell how much time would be allowed.
"If she's evaluating, a half hour ..." Wozniacki said of the trainer.
Peng returned without having to forfeit a point but was still struggling. She missed the break point as the game went to deuce, and then failed to capitalize on the other two break points she generated. Five points were played before Peng was forced to retire.
Afterward, Brewer faced questions about why Peng was allowed back on the court: Could heat illness really be properly addressed with three minutes of treatment?
"We've constantly been looking for that balance between, let's help the player protect themselves and allow them to compete as long and hard as they can," Brewer said. "The ultimate answer to your question would be: If our medical staff felt the player would endanger herself by returning to the court, they would not have allowed her to return. And they have the right to do that."
Peng said she was feeling much better and expected to fully recover.
To put a fine point on it, Peng had shown tremendous fortitude during earlier matches. She hadn't dropped a set as she took out three seeds and hadn't been broken in 40 service games until the first semifinal set.
Wozniacki didn't have any complaints about the way it was handled, and said she doesn't think the rules on breaks need to be addressed despite the length of this one.
"I believe the best in people," Wozniacki said. "I believe if you need a bathroom break, you go to the bathroom. If you need treatment, you get treatment. I don't think any rules should be changed."