Having come close to achieving dreams without sleep, Maria Sharapova is resting on Thursday in the knowledge that a perfect end to a fairytale year is within her grasp.
The game's greatest survivor overcame constant deficits in a three-hour match with Agnieszka Radwanska which finished in the early hours of Thursday morning, carrying Sharapova exhausted to her bed and to a place in the semi-finals of the WTA Championships on Saturday.
It means the tenacious Russian can still finish a character-defining season in which she completed a career Grand Slam by capturing the season-end title she last won in her breakthrough season eight years ago.
For a player who was warned she might never be the same after a shoulder operation four years ago, and who has had to compensate for a reduction in the effectiveness of her service ever since, it is all a massive achievement.
"It was such a physical match," said Sharapova after a 5-7, 7-5, 7-5 win which equalled the longest in number of games of any match in the 40-year history of the WTA Championships.
"It just came down just to a few points in the end. It was an example of not playing my best tennis at all, fighting through it, hanging in there, and getting it done.
"No matter if it's, you know, a hard shot or a lower slice that has no pace, she makes you work for it," Sharapova said of the world number four from Poland whose intelligent, varied game dominated many periods of the match.
"But I found a way to get through those points against her which is not always easy, especially on a slower court like this. I fought and I won, so I'm happy."
Sharapova covered so many acres of ground that at one point, when she managed to get Radwanska to do more of the running for a change, she appeared to give a celebratory yell of, "run, run, run!"
And the struggle was so uphill that there were times when she seemed to be disagreeing with coach Thomas Hogstedt.
"I was just aggravated because I was making errors and wasn't doing the right things," Sharapova explained.
"In the heat of the moment you've got to blame it on someone, right? It's never on yourself," she added.
"But I'm not frustrated. I'm just wondering when I'm going to sleep. Aren't we all?"
With Victoria Azarenka's earlier win over Angelique Kerber lasting a similar length of time and an identical number of record-equalling games, the day's schedule of only three matches lasted more than nine hours, ending at 2.10 am.
Radwanska, who can still qualify if she beats French Open finalist Sara Errani on Friday admitted that "for sure that match cost me a lot".
It will have cost them both, but Sharapova can rest in the knowledge that she can afford to lose her last group match, against Samantha Stosur, the former French Open champion from Australia, who has replaced the unwell Petra Kvitova, the 2011 WTA champion from the Czech republic.
She also knows that two wins have also carried Serena Williams into the semi-finals as well, and that the American is many people's favourite for the title. The Olympic, Wimbledon, and US Open champion plays Victoria Azarenka, the world number one from Belarus later on Friday.