Their first fight was a seminal moment in UFC history, even if it only lasted 64 seconds.
Junior Dos Santos and Cain Velasquez figure their rematch Saturday night will be longer, more taxing and more decisive in determining mixed martial arts' best heavyweight.
Dos Santos defends the championship belt he took from Velasquez 13 months ago when they meet in the main event of UFC 155 in Las Vegas.
Last year, Dos Santos abruptly dropped Velasquez with one equilibrium-destroying punch to the head, putting an early end on the UFC's landmark debut fight on network television.
Velasquez has been stewing on his first MMA defeat ever since, determined to regain his title. He also refuses to blame the loss on a knee injury in training last year.