The 10th round stoppage saw Joyce capture the British, Commonwealth and European heavyweight titles.
A crisp jab landed on Dubois’ bulging left eye, forcing him to his knee and a swift count out.
And a reluctant Frampton offered a brutally honest assessment from Church House as Dubois fell to 15-1.
“I thought he quit there, let's call a spade a spade, I'd rather be dragged out the ring,” Frampton said on BT Sport, with former world heavyweight champion David Haye concurring with his assessment.
"It was a close fight, but you have to call it what it is. He's a young kid, he can come back. You come back and learn. The knee spoilt it all for me, you're going to have to take a lot of criticism.
“Hopefully he can learn from this, still every chance he can move on. It shows that Daniel wasn’t ready for it.”
Dubois was actually ahead on two scorecards at the conclusion of the fight, with one judge having him up by eight rounds and the other by two. The third judge had Joyce up by two rounds.
Dubois had no excuses for his first defeat of his professional career, insisting he could not see out of his left eye.
Dubois told BT Sport: “He caught me with a good jab, it was accurate, I couldn’t see out the eye.
“It just happens, I can’t explain it. I couldn’t see out of it. I tried my best, it happened. I’m a tough guy, I’ll come again.”
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