Billed Canelo v GGG II, the fight came nearly a year to the day since a split-decision draw left Golovkin stunned.
And Triple G was stunned again with a tight decision favouring the Mexican – on the eve of his country’s Independence Day – with two judges scoring the fight 115-113 and the third 114-114.
Speaking after the fight, Canelo said: “If the people want a third fight, we will do it again. But for now, I want to enjoy the moment with my family and my people.
“But if they want us to do it again, no doubt. He’s a great fighter but I’m a great fighter and I showed it tonight.”
Alvarez’s six-month ban after testing positive for clenbuterol – he claimed the positive test came from eating contaminated meat – scuppered the first prospective rematch date earlier this year.
So expectations were high as the pair went toe to toe in the highly anticipated bout at the T-Mobile Arena.
Canelo controlled the pace but Golovkin was better with the jab in the early stages, almost a reversal of last September.
Canelo got in some strong body work in the second half of the fight but, into the 12th round, it was the champion who was pushing harder, landing a left-hook and uppercut.
Going into the final three minutes, all three judges had it at 105-104 in favour of the challenger with the Mexican’s strong chin and even stronger resolve saw him go the distance and take the straps as Golovkin tasted defeat for the first time in 40 fights.
Golovkin left the ring without speaking, but later said: “I’m not going to say who won tonight because the victory belongs to Canelo according to the judges.
“I thought it was a very good fight for the fans and very exciting. I thought I fought better than he did.”