The Dubliner's coach John Kavanagh then opened his mouth in disbelief as his man landed his punch, before the whole coaching set-up erupted in ecstasy after the 27-year-old sent Aldo to the canvas.
As the 29-year-old from Manaus fell to the ground at the famous Nevada venue, Aldo's team looked devastated, with one member - fellow Brazilian mixed martial artist, Marlon Sandro - almost in tears.
To the right of Aldo's team, official Octagon announcer Bruce Buffer simply sat there wide-eyed and aghast with his mouth slightly ajar.
Aldo pulled out two weeks before his last scheduled fight with McGregor in July, citing a rib injury, and perhaps that would have been the wiser move this time around, too.
The UFC 194 card set a new US record gate of $10.1million (£6.67m) and could also break the company's pay-per-view record of around 1.5m buys.
Saturday night's gate at the MGM Grand may have been dwarfed by the $72m achieved by Mayweather and Manny Pacquiao at the same venue last May.
But it has been bettered just 19 times in boxing history - and McGregor is just getting started.
