Roger Federer will try to make it an all-parent championship Monday as the new father of twin girls faces Juan Martin del Potro with his sixth straight U.S. Open title at stake.

Federer beat Novak Djokovic on Sunday with the help of what he called the greatest shot of his life: a between-the-legs, back-to-the-net, crosscourt winner from the baseline. A point later, with the crowd in hysterics and Djokovic still in shock, the world's top-ranked player closed out the victory, 7-6 (3), 7-5, 7-5.

The sixth-seeded Del Potro steamrolled No. 3 Rafael Nadal 6-2, 6-2, 6-2 earlier in the day to reach his first Grand Slam final.

"Right now, I'm pretty relaxed," Federer said. "We'll see how it goes when the sun comes up. I'd like to keep this going. It'd be great to get my first Grand Slam as a dad."

On the women's side, Kim Clijsters of Belgian beat five of the top 18 players in the world to become the first unseeded player to win the Open when she defeated No. 9 seed Caroline Wozniacki 7-5, 6-3 on Sunday night.

"It's a great feeling to have, but it's confusing in a lot of ways, as well," Clijsters said. "It went so quickly, everything."

No mother had captured a major since Evonne Goolagong Cawley in 1980 at Wimbledon.

"I was so very excited to hear that Kim won, and I'm so happy for her," Goolagong Cawley, who won Wimbledon three years after having daughter Kelly, told The Associated Press on Monday. "Go Moms."

Rain delayed the semifinal match between Clijsters and Serena Williams, then that match ended abruptly Saturday night in a very different kind of storm: Williams' tirade at a linesperson after a foot fault call resulted in a penalty that decided the final point of the match.

On Sunday, Williams was fined $10,000, and more punishment could follow from a broader investigation.

The ending left Clijsters stunned instead of celebrating her stellar play. But the break from tennis and motherhood have left the 26-year-old wiser than the last time she played the Open -- when she won her lone previous major title in 2005.

"Because I've become a lot more understanding of myself, you know how to deal with it when different emotions come up," Clijsters said.

Lacking motivation, disheartened by a series of injuries, and yearning to start a family, Clijsters had retired. She didn't think about competitive tennis until she started training again at the start of the year.

"She's playing because she thinks it's fun and because she likes it," Wozniacki said. "I really think she might be a better player now than she was before."

What if somebody had called her in the hospital after Jada was born and told her she'd be back playing tennis in 18 months?

"I would have gone, 'Click,"' Clijsters said, laughing as she pantomimed hanging up a phone.

Clijsters beat both Williams sisters along the way, matching them power shot for power shot, then showed she could endure the 19-year-old Dane's patient game.

Clijsters didn't have a ranking coming in because she hadn't played enough tournaments to get on the list. She'll come in at around No. 20 when the new rankings are released this week.

On Sunday, Jada took a nap a bit later than usual so she could stay awake for the match.

"Brian and I were a lot more nervous than she was," Clijsters said. "She just thought it was the most normal thing."