Clijsters made history Sunday night, capping a comeback from two years out of tennis to become the first unseeded woman to win the Open - and the first mom to win a major since 1980 - with a 7-5, 6-3 victory over No. 9 Caroline Wozniacki.
When it was over, Clijsters collapsed to the ground and started crying - tears of joy, probably mixed in with a little bit of shock, too. Her 18-month-old daughter, Jada, watched from a suite with a pacifier in her mouth, but later came down to the court to take part in the celebration.
Guess what mommy got for you, sweetie! A Grand Slam title. "It was not really our plan," Clijsters said. "I just wanted to start these three tournaments and get back into the rhythm of playing tennis and get used to the surroundings again." Talk about your quick transitions.
It was all quite a different scene from the night before, when Clijsters' semifinal win over Serena Williams was decided on a point penalty, and the 26-year-old Belgian stood behind the baseline, looking bewildered as Williams ran over to shake her hand.
Williams' tirade may have been the talk of the U.S. Open. But Clijsters was the winner. This was her second U.S. Open title, the other coming in 2005 - her last appearance at Flushing Meadows and before a spate of nagging injuries eventually drove her out of the sport and led her to start a family.
Some might have called this the mother of all upsets, but by the time she reached the final, against the resilient but still-learning 19-year-old from Denmark, it was hard to view it that way.
Clijsters beat both Williams sisters and two players seeded in the teens. She matched Venus and Serena power shot for power shot and showed she could play Wozniacki's patient game - and play it better.
This one was nothing like the Williams match - before it turned sour - which was filled with short, hard-hitting rallies in which Clijsters moved one of tennis' best players at will and made her hit shots from places she normally doesn't.
Instead, it was a waiting game, and when Clijsters fell behind 4-2 in the first set, she showed she was willing to play it.
A 29-shot rally here, a 25-shot rally there. Drop shots and lobs. Clijsters did that. Went for more, too, and finished with two more winners than unforced errors (36-34) - a good ratio on any day - and 26 more winners than Wozniacki.
After getting back on serve, Clijsters held off two break points at 5-5, then broke Wozniacki for the fourth time to win the first set. The second set was easier and before they knew it, Jada was on the court posing for photographers.
Clijsters didn't even have a ranking coming into this tournament 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, but probably won't try to improve on that right away.
"It's the greatest feeling in the world being a mother," she said. "I just can't wait to spend next the few weeks with her and have her routine schedule at home again."
Her victory came over the first Danish player to reach a Grand Slam final, though Wozniacki's greater claim to fame is that she has won more matches on tour this year than anyone.
She played like a winner over two weeks in Flushing Meadows, including that 6-2, 6-2 victory that ended the magical run of 17-year-old Melanie Oudin, whose rapid rise was the story of the tournament for the first 10 days.
Oudin left, then the Williams imbroglio took over.
Clijsters made her headlines, too. The mother-on-a-comeback story was a winner all the way.
Beneath the surface of all these stories might also be a referendum on the state of women's tennis. If an unseeded mother who has been away from the game for two years can beat five top-20 players and win the U.S. Open, maybe the talent pool isn't so deep. In fact, stories circulated recently that former No. 1 Justine Henin might be making a comeback, too.
Could Evonne Goolagong Cawley be far behind? She was the last mother to win one of these Grand Slams, back in 1980 at Wimbledon. Clijsters last major title isn't that sort of ancient history. It was only four years ago that she climbed into the stands and tightrope-walked across the railings to celebrate her first U.S. Open title.
Same scene this time but with a few new players. There was her husband, American Brian Lynch, with whom she shared a long, sweet kiss. Then there was Jada, clapping her hands with that binky in her mouth.
"We tried to plan her nap time a little later today so she could be here," Clijsters said.
Looks like she's getting the hang of that motherhood thing, too.