After losing a fourth straight major final, will Serena Williams ever make it to her stated goal of 24 grand-slam titles? The question carries a weight that extends beyond the American player's personal ambitions.
Many would like to see the name of Margaret Court - now a Pentecostal pastor with extremely illiberal views - knocked off the top of the table.
On Saturday night, as the match ebbed away from Williams, it was noticeable that Billie Jean King's partner, Ilana Kloss, had her head in her hands at the side of the court.
Williams insisted afterwards that the quest would go on. But there was a Groundhog Day feeling on Arthur Ashe Stadium, as the final continued the pattern of Williams's three previous trophy matches. While her 19-year-old opponent, Bianca Andreescu, delivered a majestic performance, it was equally true that she was heavy-footed and indecisive.
At one point, she pulled out of a backhand mid-swing, allowing the ball to bounce up higher before taking a second attempt at the shot. It was the sort of nervy recalculation you would expect to see from a weekend player on a park court, not an all-time legend whose coterie included the Duchess of Sussex.
By contrast with last year's defiant post-match press conference - when Williams had accused chair umpire Carlos Ramos of sexism - she was tearful and unusually contemplative in the interview room after her 6-3, 7-5 defeat.
"I love Bianca," Williams said. "I think she's a great girl. But I think this was the worst match I've played all tournament. It truly is super frustrating. I'm, like, so close, so close, so close, yet so far away. I guess I got to keep going if I want to be a professional tennis player."
Speaking to reporters on Saturday night, Williams's coach, Patrick Mouratoglou, did not deny rumours that his charge would sit out the rest of the season, only returning to the court in time for January's Australian Open.
"We didn't decide yet," he said. "I don't know if she will be at the WTA Finals [the season-ending tournament which finishes on Nov 3]."
But Mouratoglou was bullish about Williams's prospects of eventually equalling Court's record. "She is not a quitter. Yes it's tough, but being a champion is not giving up when it's tough. We are going to make this 24 or 25.
"The thing we need most is time," he added. "She is coming back not from an injury but being a mother. It's a huge transformation both for the body and the mind and at her age [Williams turns 38 this month] it takes even more time."
According to Mouratoglou, Williams's job has been made harder by the fact that her opponents in all four finals "had zero pressure". Yet it is hard to see that changing.
Williams already towers over the sport like the Statue of Liberty over the Hudson River, and all the expectation and attention is naturally drawn towards her. With every tournament, too, the sense of time running out becomes more acute.
What a contrast, then, with new champion Andreescu. Not only does this beguiling player have decades in front of her, she also makes this whole tennis lark - which reduces many aspiring champions to despair - seem bewilderingly easy and stress-free. Admittedly, Andreescu had one tearful moment of her own in her post-match press conference, when she explained that "I've been dreaming of this moment for the longest time". For a few seconds, she held her hands over her face and sobbed. But when an official asked her whether she needed a break to compose herself, she straightened up, grinned and replied: "I'm good. Continue."
Andreescu's elevation has come so quickly that, even at the start of this season, many tennis insiders had no idea who she was. She has skipped an entire stage of development, like a butterfly who somehow never had to be a caterpillar.
There is an echo of Monica Seles, who also won the fourth major she entered: the French Open of 1990. Except that Seles was only 16, and had reached the semi-final of Roland Garros a year earlier, so she was hardly an unknown quantity.
In Andreescu's case, she was just another promising teenager training at the IMG Academy in Florida during the off-season. In fact, she spent a lot of time with the British party posted out to Bradenton by the Lawn Tennis Association, becoming friendly with the likes of Katie Boulter and Cameron Norrie.
Since then, though, she has gone through the gears at speed, first reaching the final of Auckland in January and then lifting significant titles in Indian Wells and her home city of Toronto. Now ranked world No 5, Andreescu has just become the first Canadian to win a major.
After her press conference, Andreescu's understated coach, Sylvain Bruneau, was presented with a trophy of his own. "I'm not used to this," he said, trying to find a comfortable way to pose for the cameras. His young client grinned. "We'll get used to it," she said.