The Bell Centre in Montreal was rabid in support of hometown hero St-Pierre, losing their minds from the entrances and introductions and loudly booing Diaz at every turn.
Diaz is a legendary striker, renowned not only for throwing them in bunches but for landing a high percentage of them. He was hoping to keep the fight a stand-up battle heading in, while St-Pierre was hoping to go to the ground. In the first round, St-Pierre scored an almost immediate takedown, but Diaz fought well from his back.
St-Pierre kept battling, landing some shots as the two men grappled on the ground and then getting side control before getting back on top in the guard. Diaz kept attempting to escape and briefly regained his feet against the cage, but St-Pierre was able to take Diaz's back several times as the crowd chanted in their support. St-Pierre scored another takedown toward the end of the first round, which he thoroughly dominated.
In Round 2, St-Pierre quickly took Diaz down again. While there are few fighters more skilled at evading grapples and fighting from their back, Diaz was unable to counter the strength and ability of St-Pierre. An attempt at a leg lock was met with a big knee to the body. Diaz landed a couple of shots from his back, but St-Pierre dropped a big elbow to silence the burst of offense. Both men stood and traded in the final minute and when the round was over Diaz took a few seconds to jaw with St-Pierre.
In typical Diaz fashion, he began the third round by taunting St-Pierre, trying to sucker him into charging. St-Pierre landed a couple of shots and went for a takedown, which Diaz avoided, but he then managed a successful takedown. Diaz regained his feet and avoided another takedown, then managed to land a big body shot as the two men traded blows. Both fighters went for showy crescent kicks that missed, then St-Pierre landed a big combination. Diaz was able to stifle yet another takedown, then landed some significant shots before being taken down again. Diaz took a swing from his back after the horn sounded and he was warned by the referee. It was the closest round of the fight, but Diaz headed into the fourth round knowing he either needed to finish or needed two dominant rounds to take a decision.
In the opening minute of Round 4, Diaz stopped three-straight takedown attempts and landed a good combination, but St-Pierre answered back. St-Pierre finally managed a takedown with under 2:00 left in the round, then slammed Diaz once more for a seventh takedown when Diaz regained his feet. Diaz tried for a leg lock in the final seconds but it was to no avail.
Heading into the final round, Diaz knew he had to go for broke. St-Pierre stood and traded with Diaz for nearly two minutes, seemingly giving the challenger every opportunity to capitalize using his desired game-plan. St-Pierre scored a takedown and controlled on top, but Diaz escaped with just under 2:00 left in the fight. They briefly traded again before St-Pierre once again scored a takedown. Diaz went for a desperation triangle in the final seconds, but it was no use.
The two men embraced after the fight and St-Pierre had nothing but nice things to say about Diaz in his post-fight in-ring interview. Diaz returned the favor in his interview and obliquely hinted that he might be thinking about retirement.
The judges awarded St-Pierre the unanimous victory on scores of 50-45, 50-45, 50-45. With the win, St-Pierre improves to 24-2 and has not lost a fight since 2007. Diaz falls to 26-8 in his professional career.