"This was never really the plan," Clijsters said, adding she never thought she'd return to professional tennis.
Slideshow: U.S. Open 2009: Final Weekend Photos
Clijsters came back to competitive tennis this year when she was invited to Wimbledon to play in an exhibition match. She said she just wanted to be in shape to play tennis greats such as Andre Agassi and Steffi Graf.
Unseeded Clijsters Wins U.S. Open Title
But when she got a taste of competition, she said, the hunger to play returned.
Clijsters said, "In the beginning, I kind of tried to just push it aside a little bit. because I didn't know if it was a feeling that was going to stay, but it did. And I'm very happy that I got the chance and the opportunity to do it."
Clijsters, of Belgium, defeated Danish No. 9 seed Caroline Wozniacki with a 7-5, 6-3 victory. This is the second U.S. Open title for Clijsters. Her first Open victory at Flushing Meadows was in 2005 -- her last title before injuries pushed her into retirement.
However, while in retirement, Clijsters married American Brian Lynch and gave birth to a baby girl, Jada. The 26-year-old player is the first mother to win a tennis major since Evonne Goolagong Cawley won Wimbledon in 1980.
Clijsters said the moment she shared with her now 18-month-old daughter was "very special." Clijsters said she's been getting adjusted to being on tour again -- and now as a mother. She said she changed Jada's nap schedule so she could attend the match.
"My husband was there, as well," she said. " ... They weren't there when I won it the first time, so it was nice to share it with them."
The road to her win at the Open victory wasn't without its controversies, however.
During the semifinals, last year's champion, Serena Williams, yelled what were said to be profane remarks at one of the line judges after a foot fault call during a pivotal point in a match against Clijsters.
U.S. Open Fines Williams $10K for Tirade
But Clijsters kept out of it. She said on "The Early Show" she didn't know what was happening on the other side of the net.
"I actually didn't hear much, just because I was just so focused on just trying to finish that match," she said. "And I had a really good feeling out there. I was seeing the ball really well and playing really good tennis, so I didn't want to distract me, so I stayed against the back of the court and didn't hear much until the day afterwards."
Williams lost the match after a point penalty for her behavior. Williams crossed the net and explained to Clijsters what had happened. Clijsters said Williams wished her good luck on the rest of the tournament.
"It was unfortunate that it had to end that way," Clijsters said.