How it unfolded
On the morning of the fight, 23-year-old Jon Jones was jogging with his coaches in a park in Paterson, New Jersey, when he spotted, chased down and detained a robbery suspect, then fought for the title that same evening. His opponent was PRIDE Grand Prix winner and reigning light heavyweight champion Mauricio 'Shogun' Rua. From the opening round, Jones used his roughly 84.5-inch reach to control distance with side kicks and spinning elbows, and landed knees and elbows in the clinch every time Rua tried to close the gap. In the second round, he scored a takedown and stacked elbows from the top. At 2:37 of the third round, a series of knees to Rua's body, backed against the cage, buckled him and the referee stopped the fight. Jones became the youngest champion in UFC history at 23 years and 242 days old. He would go on to defend the belt eight times through 2015.
Why it still matters
A generational changing of the guard was completed in a single fight. A champion who symbolized the PRIDE era was thoroughly beaten by a new kind of fighter built on physical gifts and creative striking, and light heavyweight revolved around Jones for the next decade. His youngest-champion record still stands.