Her loss to Bianca Andreescu marked her fourth consecutive defeat in a Grand Slam final. For the moment, at least, she soldiers on.
The handwriting was not only on the wall for Serena Williams in this instance. It was on the cheque.
Bianca Andreescu, even at age 15 in 2015, knew what she wanted and, above all, what was possible. So back then she wrote herself a personal cheque for the amount won by the champion of the US Open.
On Sunday, after beating Williams, 6-3, 7-5, for the title, she got the real deal: prize money of US$3.85 million ($6m).
"Oh my God," Andreescu said.
A few hours later, I asked Andreescu if, when she was younger, she had written any cheques to herself for winning the other three Grand Slam tournaments: Australian Open, French Open or Wimbledon?
"No, only the US Open," she said. But, she added, "maybe it's time."
Andreescu, a Canadian teenager with so much talent and no shortage of charisma, has every right and reason to keep dreaming bigger.
Of all the talented youngsters storming the citadel of women's tennis, she has the most complete game and the best big-match temperament. Staying healthy has been a challenge, but she is 8-0 against the top 10 in her short career, with all those victories coming this season.
"She's the best of them all," Carling Bassett-Seguso, Canada's first teenage tennis prodigy, said of Andreescu's standing in the new generation of top players.
Bassett-Seguso reached the US Open semifinals at age 16 in 1984 and peaked in the rankings at No. 8. Andreescu will be No. 5 on Tuesday.
"I slept maybe two hours last night because I was so excited for her," Bassett-Seguso said. "She's fierce on the court but she's also humble in her comments, and I can see her being a phenomenal ambassador in the future, not just for Canadian tennis but for sport and for women."
Like other WTA youngsters, Andreescu is getting the precious opportunity to make a name for herself by playing against Williams, the greatest player of this era.
Beating Williams has an amplifying effect beyond compare in the women's game, and though Williams is above all interested in winning more titles herself as she soldiers on at age 37, her enduring presence and relevance are also boons to her sport.
Nothing helps a new arrival become a superstar the way defeating a superstar in a Grand Slam final does.
Think back to Steffi Graf, who arrived and toppled Martina Navratilova and Chris Evert. Think back to Monica Seles, who arrived and soon defeated Graf. Think back to Williams herself, who arrived in her sister Venus' shadow and then seized the spotlight by upsetting Martina Hingis in 1999 to win her first Grand Slam singles title at the U.S. Open at age 17.
"It goes full circle," Evert said Sunday. "I was a teenager who had no pressure and beat the top players like Billie Jean King and Margaret Court when they were at the end of their careers. Steffi beat me at the end of mine. What goes around comes around. Serena is learning that now, but you have to and should play both roles if you want longevity."
Was Andreescu intimidated by the Williams aura Sunday?
"Of course," she said after a pause. "I just prepared myself the best way I could, like I do every match. But having that opportunity to play against her and then actually winning the match is just so crazy."
No longer as crazy as it would once have seemed. Williams won 21 of her first 25 major singles finals. But she has won just two of her last eight and has lost four straight since returning to the tour last season after giving birth to her first child.
Her comeback has inspired many others, including her friend Allyson Felix, the American track star, who nine months after her pregnancy won a 150-meter race in Stockton, California, on Saturday.
But the more that Williams falters in big matches, the more empowered all of her potential rivals become.
Her last four defeats in major finals — all straight-sets losses — have come against four different players.
Two came at Wimbledon against established figures: Angelique Kerber and Simona Halep, who both had won major titles and reached No. 1 in the rankings.
The other two defeats came at the US Open against new arrivals: Naomi Osaka, who was 20 when she beat Williams in last year's final, and Andreescu, who is 19.
Williams also lost in straight sets in the third round of this year's French Open to Sofia Kenin, a 20-year-old American.
That is a lot of empowerment, and it is unlikely to get easier for Williams, even if she beats the odds by staying healthy and being able to consistently train and compete, which has not been the case for much of this injury-filled season.
Patrick Mouratoglou, her coach, lobbied Sunday for Williams to push on and keep chasing more success.
"There is always the option to give up, advised by those who let their frustrations rule their opinions," he said in a message posted on social media. "The other option is to continue the fight for winning other majors. It is a deep pain to work so hard, give it all, and fail."
Mouratoglou continued by saying one of the characteristics of a champion is "to never give up, whatever they go through, until they reach their goal."
"Serena is the ultimate champion," he said. "Sport can be ruthless, but that is also why we love it."
The question is how much disappointment Williams is prepared to take at this late stage of her career.
It could be a tough call. The signals are mixed. She has shown dominant form on her way to major finals. She beat 18th-seeded Wang Qiang, 6-1, 6-0, and fifth-seeded Elina Svitolina, 6-3, 6-1, before facing Andreescu. At Wimbledon this year, Williams overwhelmed Barbora Strycova, 6-1, 6-2, in the semifinals before losing in a hurry to Halep.
Is it a mental block? Or is it more about regime change, with more players of all ages now capable of absorbing Williams' power and competitive fury and showing swagger of their own under Grand Slam pressure?
For now, it looks like a combination. Williams came out of the starting blocks Saturday as if she were intent on overwhelming Andreescu with her serve and baseline punch.
But when Andreescu showed an ability to hit deep, penetrating returns off many of Williams' serves, Williams began to force the issue and overhit. She ended up making a tournament-high eight double faults and a tournament-low 44& of her first serves into play, which was partly a credit to Andreescu's pressure. Williams' season average is 60 per cent.
"That was part of the whole plan, just to make a lot of returns so she could feel I'm not intimidated by her serve," Andreescu said.
Williams often showed her frustration instead of staying focused and made the sort of off-balance errors with her groundstrokes that have long been a reflection of inner tension.
Yes, she rallied from 1-5 down in the second set to 5-all, but she lost her edge again and seemed both tight and slow to react in the final two games of the match as Andreescu fought back to become the first Canadian to win a Grand Slam singles title.
Ending that drought would always have been cause for celebration and attention. Ending it against a champion of Williams' stature only magnified it.
Written by: Christopher Clarey
© 2019 THE NEW YORK TIMES