Instead, he must now reset and recharge to go again at Wimbledon next month.
Given he is a seven-time champion on a grass surface which younger players have struggled to master, Djokovic will always fancy his chances at the All England Club.
Djokovic can never be ruled out of becoming the oldest major men’s singles champion in the Open Era, but Father Time has been sat waiting on Djokovic’s shoulder for a good while.
By rights, he should probably be basking in a post-retirement glow by now.
Coaching a young compatriot away from the public glare like Andy Murray, perhaps. Doing a promotional tour for a new Netflix documentary like Rafael Nadal, maybe.
While his long-time rivals move into the next phase of their lives, Djokovic was retching at the side of a court in an attempt to summon the energy to beat a teenager.
It is a testament to his superpower that he still wants to push himself to such limits against much younger opponents.
As we have seen time and time again, Djokovic’s insatiable appetite for the sport’s biggest prizes will never diminish.
But, having reached at least the semi-finals at the past five Grand Slams, this was the clearest sign yet that the ageing process was finally catching up with him.
Djokovic looked in complete control as he moved two sets ahead, but could not maintain his level as Fonseca proved he is the real deal.
“It would be nice if it was best-of-three,” Djokovic smiled.
“I just ran out of gas, to be honest. I didn’t feel good at all on the court in the next couple of sets.”
Djokovic has always thrived in the best-of-five format of the majors, beating almost anybody who has stood in his way for almost two years.
The only exceptions have been Jannik Sinner, Carlos Alcaraz and the knee injury which forced him to quit against Alexander Zverev at last year’s Australian Open.
Everyone else has not been good enough, or not had the mentality, to see veteran Djokovic off.