LAS VEGAS -- A year's worth of buildup needed just 13 seconds to resolve.
A huge left hand to the jaw followed by a couple of hammerfists was all it took, as the pride of Dublin won the UFC featherweight championship before a delirious, partisan Irish crowd at the MGM Grand Garden Arena.
"He's a phenomenal warrior and a phenomenal champion," said McGregor (19-2), who won his 15th consecutive fight. "He deserved to go a little bit longer."
McGregor sidestepped a charging Aldo and landed a magnificent left hand to the jaw, which stopped Aldo cold. McGregor landed a couple brutal hammer fists to the downed Aldo before referee John McCarthy called off the fight.
"No power, just precision," said McGregor. "No speed, just timing. That's all it takes, especially when you have my left hand. Nothing can take that left hand."
It was a staggering end to a year's worth of drama. The bout was originally slated for UFC 189 in July, but Aldo had to drop out due to a rib injury. McGregor finished replacement Chad Mendes in the second round to claim an interim title.
Aldo, who had been champion since winning what was then the WEC title from Mike Brown in Nov. 2009, had an 18-fight win streak snapped.
"I threw a punch and he came back with another cross and that was it," said Aldo (22-2). "I think we need a rematch, it wasn't a fight."