A shattered de Minaur was planning to fly out from Beijing to Shanghai, where he'll get tests to discover the extent of the adductor injury which could keep him out of the Masters 1000 event.
Pulling out when 7-6 (7-3) 0-1 down to the amazing Djokovic on Tuesday demonstrated the potential seriousness of the problem as there would have been no way otherwise the Australian fighter would have retired while battling for arguably the biggest match-win and title of his career.
"I was feeling quite good, then felt something midway/end of the first set that gradually got a little worse," explained de Minaur after Djokovic had won his 102nd career title despite his own physical struggles.
"I felt something in the adductor. I don't know what it is yet. I've got to get some more scans. My plan is to go to Shanghai and get scans."
After Jannik Sinner's revelation on Tuesday that his season's over because of knee trouble, de Minaur is now eighth in the Race to Turin live standings, which would get him in the end-of-season ATP Finals again should he maintain that position.
But it's a tight turnaround with the Australian set to open his Shanghai campaign on Friday or Saturday.
"I don't feel great," de Minaur sighed, apologising to the Chinese National Tennis Centre crowd for his withdrawal.
"I didn't want to finish like this, so really, really sorry."
The extraordinary twist after a high-quality tussle was that it had been Djokovic who'd looked far more likely to retire after calling for the trainer to treat his continuing unspecified on-court medical ailments that have beset him all season.
But after Djokovic's on-court treatment following a tight first set which was eventually decided after 67 minutes by three de Minaur forehand errors in the breaker, it was de Minaur's turn to immediately receive an off-court medical timeout, even though there'd been no signs of a problem.
When he returned, his left thigh heavily strapped, and held serve impressive to launch the second set, there was shock all round as de Minaur suddenly approached the net gloomily to offer his hand, explaining he couldn't carry on.
It was an anti-climactic end to a brilliant, lung-busting contest, with the 39-year-old Djokovic, incredibly, celebrating his first triumph of the year to maintain his unreal record of a tournament win in each of the last 21 seasons.
Even de Minaur felt moved to tell Djokovic: "It was pretty amazing as a fan of the sport to watch the tennis you produced this whole week."
Djokovic, in response, told de Minaur after lifting the trophy for the seventh time and continuing his unreal record of 34 match wins and no losses in Beijing: "I'm really sorry for the way it had to finish today and I hope you can recover quickly."
After Daniil Medvedev had a day earlier been defaulted for hitting a spectator in the face with a ball petulantly swatted away, Djokovic mused: "I don't think it's happened ever in my career that I have won semis and finals without finishing the match - a bit of a strange feeling.
"I want to celebrate because I've played one of my best weeks in the last couple of years, but at the same time, Alex retired so it doesn't kind of feel right and respectful to jump around and be joyful.
"But deep inside, I'm very, very proud of this achievement. It's been a challenging year. Many times I've questioned whether I want to play, keep on playing this way, but this week has proven me wrong once again and given me a great confidence boost for the rest of the season."
As for 'Demon', it's not all been so deflating amid a promising late-season renaissance. "I played some great stuff, felt amazing on the court," he sighed. "Everything except for the end was really positive."
