An epoch-shifting Grand Slam season dominated by Jannik Sinner and Carlos Alcaraz has provided the clearest sign yet that the "Big Three" era of men's tennis is finally over, with Novak Djokovic destined to be its last year-end No 1.
The golden rule that you should never write off Djokovic still holds true, but after he, Rafael Nadal and Roger Federer had won at least one Grand Slam title between them every season since 2003, this year there were none.
Sinner lifted the US Open title on Sunday following his breakthrough Australian Open triumph in January, while Alcaraz won the French Open and Wimbledon to mark the first time since 1993 that men aged 23 or under had swept the Grand Slams.
"It's a bit different, for sure. It's something new, but also nice to see," said Sinner, who overcame the distraction of a doping controversy to help usher in a new age.
"It's nice to see new champions. Nice to see new rivalries. I feel it's good for the sport to have some new champions."
The extraordinary dominance of the "Big Three" saw them win 66 of 81 Grand Slam tournaments from Federer's first Wimbledon title in 2003 to Djokovic's 24th major title at Flushing Meadows last year.
With Federer retired and Nadal hampered by injury, Djokovic single-handedly held back the younger generation in 2023 by winning three of the four majors and finishing as the year-end No 1 for a record-extending eighth time.
This year, Djokovic endured a lacklustre Grand Slam campaign by his lofty standards, starting with a semifinal loss to Sinner at Melbourne Park and continuing with an injury enforced withdrawal from the quarterfinals at Roland Garros.
Mauled by Alcaraz in the Wimbledon final, he suffered a chastening defeat by Alexei Popyrin in the third round of the US Open and was shut out of the majors for the first time since his injury-plagued 2017 season.
He did, however, produce a miraculous effort to stave off much younger rivals at the Paris Olympics, including Alcaraz in the final, and claim the gold medal he had long coveted.
"From a larger perspective, of course I have to be content," Djokovic said in the aftermath of his US Open exit.
"It's hard to see the big perspective right now. You're just angry and upset that you lost and the way you played. But tomorrow is a new day. I'll obviously think about what to do next."
IMPOSSIBLE TASK
Having turned 37 in May, Djokovic is already past the age at which any man has won a Grand Slam title and finishing the season at the top of the rankings looks an impossible task in the twilight of his career.
Djokovic is ninth in the race to the season finale in Turin - the separate year-to-date standings that serve as a measuring stick for the battle for No 1 - and is unlikely to gain much ground in the Asian swing starting this month.
A more important target for a man who has always had a huge regard for the history of the game might be winning a 25th Grand Slam to surpass Margaret Court's record.
Nowhere is that more likely to happen than at January's Australian Open, where Djokovic has lifted the trophy a record 10 times in 19 appearances.
"You never want to count him out," seven-time major champion John McEnroe told Eurosport.
"This would certainly be the first time where you could say with some seriousness that you start to wonder if he's going to win (a major) again.
"I'm sure to be surprised either way. If he doesn't win, you'd be like 'wow, he won three of the four last year and now we're saying he'll never win it again'.
"And then I would be surprised in a way if he did, because of his age. At some point, that catches up to you and you lose a little bit of that fear factor with some of the guys."