The kick, set up by some heavy left hands from Holm, sent an unconscious Rousey with a badly split lip crashing to the canvas then straight into hospital for the night.
Her representatives denied she had a concussion, despite UFC President Dana White saying as much in a press conference.
The irony was thick as White's golden girl suffered her first loss inside the Octagon, after she had entered, as usual, to the soaring vocals of Joan Jett screaming "I don't give a damn about my reputation".
But while it might have been the fall of a champion, the rematch is already being talked about.
The quality of the fights on the undercard and how well Australians and New Zealanders alike acquitted themselves impressed White.
Dubbo fighter Kyle Noke collected a $50,000 bonus for the performance of the night after he landed a huge front snap kick into Peter Sobotta's abdomen, ending the fight at the 2:01 mark of the first.
When 35-year-old Noke crashed his hoof into his foe's midsection, Sobotta cried out in agony and crumbled in a heap.
And that was just the beginning. Jake Matthews, 21, moved to a 3-1 UFC record, with doctors stopping his fight against Akbarh Arreola of Mexico, after a brutal elbow split the Mexican wide open above the eye.
Dan Kelly was also impressive and Mark Hunt made a statement to the heavyweight division, knocking Antonio Silva out in the first round of their match.
The Auckland-born fighter followed up a glancing right to the jaw with a huge uppercut to the kneeling Silva, at which point the referee awarded the TKO to the big-hitting Kiwi.
But the man who really impressed White was middleweight contender Robert Whittaker.
The 24-year-old moved to a 16-4 record with an entertaining, unanimous decision victory over Jamaica's Uriah Hall in one of the best fights on the card.
"They were not just great fights, they were awesome," chirped White of the undercard.
"I have been watching Whittaker for a while and he is one of the real up and coming guys in the UFC."
The UFC said it was very happy with the response of Melbourne fans and would next head to Australia for a Fight Night card in Brisbane on March 20, 2016.
- AAP