When Caroline Wozniacki announced to her father/coach Piotr that she was going to run in this year's New York City Marathon, his first reaction was to tell her she was crazy.
Just as Wozniacki was rounding into form after a series of early season distractions, it appeared as though she had latched onto something that would again harm her tennis game.
But Tuesday night, in a three-hour and 13-minute match, the third-longest match in WTA Finals history, Wozniacki's marathon training may have actually paid off. She outlasted Maria Sharapova, 7-6(4), 6-7(5), 6-2 in a pulsating, intense match that kept the Singapore audience riveted from start to finish.
The victory put Wozniacki at the top of the White Group and in this round robin tournament gives her a very decent shot of moving on to the semifinals.
"I just feel like right now with all the training and running I've been doing, I can keep being out there and keep running," Wozniacki said. "I kept thinking to myself out there in the third set, 'If you're going to get tired now, how are you going to get through this marathon? You better keep going.' I did, and I felt pretty good out there. I felt I could still keep going for a while."
This does not bode well for future opponents, including a potentially rested Agnieszka Radwanska, who beat Petra Kvitova in straight sets on Tuesday. Opponents will be well-advised to consider strategies that are not designed strictly to test Wozniacki's fitness.
"It's not a secret, she's always been one of the most physically challenging players to play against," Sharapova said. "She gets many balls back and makes you hit an extra ball. I think she's doing that better. She's improved her strength in doing that. There is a little more when she's on the defense. Not just the ball up in the air, but she has something on it. She gets herself back in position."
And while the marathon training has helped Wozniacki reach new levels of fitness, she said she'll probably avoid moonlighting as a runner until tennis is over.
"I probably wouldn't recommend it to other players," she said. "It's helped, but I don't think it's something that I want to do every year. Running a marathon and doing this much running, it's not easy. I think to do it once while you're playing is enough.
"At the same time, it gets me in great shape. To do it year in and year out, I don't think it's possible. Our bodies get a beating already. I don't think it's necessary to do this again while I'm on tour."