Caroline Wozniacki's legs quivered with cramps and tears flowed from her eyes as she gritted her teeth and tried steadying herself with her yellow-and-black Babolat racquet she wielded like a cane as she hobbled around the court with perspiration pouring from her pores amid the heat in Doha today.

Desperately trying to close out her round-robin match against Vera Zvonareva, Wozniacki was doing everything in her power to make a stand in the final stages —only remaining upright did not appear to be an imminent option as she was beset by crippling cramps that caused her to crash to the court in the final game.

The fourth-ranked Dane squandered a one set, 5-2 lead and two match points, a third-set collapse to the court caused by leg cramps, but still steadied herself and hung on to fight off both the cramps and Zvonareva, 6-0, 6-7(3), 6-4 in a physically grueling two hour, 48-minute victory that tested the legs, lungs and wills of both women.

"When it was 3-1 for me [in the final set] I got the cramp in my leg," Wozniacki said. "From there, it just got worse and worse. I have absolutely no idea how I pulled it through. I’m gonna do everything I can to get ready for tomorrow. I’m just going to do everything that the physiotherapist and the doctors are saying: drinking a lot of fluids, eating some good food, stretching, get some massage, get some ice massage, take a salt bath, everything."

It was Wozniacki's second straight marathon match in the heat of Doha. Yesterday, a willful Wozniacki fought off two match points in the final set to score a thrilling 1-6, 6-4, 7-5, victory over Victoria Azarenka in a match that spanned two hours, 58 minutes. Wozniacki raised her record to 2-0 in the White Group of the round-robin event.

Zvonareva, the 2008 Doha runner-up to Venus Williams, was a tournament alternate this week forced into action when World No. 1 Dinara Safina withdrew from the tournament with a lower back injury after two games against Jelena Jankovic on Tuesday.

It was a match of momentum shifts and high drama as Zvonareva, who beat Wozniacki in their lone prior meeting, 6-4, 6-2, in the Indian Wells quarterfinals in March, lost 11 of the first 13 games only to battle back from 0-6, 2-5 down and force a second-set tiebreaker. During her rally, Zvonareva took time out for treatment of an ankle injury and nose bleed.

Shrugging off the wear and tear from her near three-hour struggle with Azarenka, an eager Wozniacki came out striking the ball cleanly and moving quickly in anticipating Zvonareva's response. Wozniacki broke serve three times and required a mere 22 minutes to score the shutout in the opening set. But after building a 5-2 second-set lead on the strength of back-to-back love games, Wozniacki was forced to sit and wait as Zvonareva, who has been troubled with nose bleeds on court in the past, took time out to treat her nose bleed.

When play resumed, Wozniacki began playing more predictable patterns to the Zvonareva backhand, which is her best shot. Pressure tightened Wozniacki's right arm when she served for the match at 5-4. Her forehand began to fail her and Wozniacki wilted, dropping the game at love. She held a pair of match points in the 11th game, but Zvonareva saved both of them. The drama heightened on the second match point when Zvonareva's forehand down the line was called wide, but she challenged and Hawk-Eye showed the ball had touched the line.

Wozniacki blew an early tie break lead then committed a double fault to face three set points. Zvonareva converted the first to level the match.

Shaking off her blown opportunity to sweep the match in straight sets, Wozniacki refocused and slammed a smash crosscourt to break in the opening game of the final set. Wozniacki consolidated the break with a service hold at 30 to take a 2-0 lead. She again appeared to be in control, but began limping and took treatment for cramps.

Serving for the match at 5-4, Wozniacki began weeping in pain. When she missed a forehand that would have given her double match point, her legs began quaking with cramps, she collapsed to the court and found herself face down prone for a few seconds. Scraping herself off the court, Wozniacki arose and served with tears falling down her face. She missed another forehand to face break point, but saved it on a Zvonareva error. Two points later, Wozniacki finally ended the two hour, 48 minute fight when Zvonareva committed a final error.

As her parents embraced in the player box, Wozniacki, seemingly struggling with each step, hobbled to the net for the post-match hand shake.