Former world number one Caroline Wozniacki knows just what to expect when she steps on a tennis court, but tackling the New York City Marathon is another matter.

"I'm a little nervous," the Dane admitted on Wednesday as she looked ahead to her first crack at the 26.2-mile distance on Sunday.

"This is the farthest I'm going to run so far. I think it's going to be an unbelievable experience. The New York City Marathon has always been on my bucket list."

Wozniacki decided to make the fantasy a reality back in June -- not long after the break-up of her engagement to golf star Rory McIlroy. Since then she has squeezed her training runs in when she can during a busy tennis season that included a runner-up finish at the US Open.

She arrived in New York on Tuesday night via Denmark from Singapore, where she played in the WTA's season-ending championships.

Since falling to Serena Williams in the US Open final , Wozniacki has played four tournaments in Asia.

In the early stages of that swing, her match schedule precluded serious marathon training and she was "starting to panic."

"I had a few dreams where I didn't finish and had to be carried through with a wheelchair," she said.