But in almost-shocking fashion, Alvarez was successful in doing something no previous Golovkin opponent had been able to do by forcing the fearsome GGG to take a step backwards during the middle rounds as Alvarez's speed and activity appeared to fatigue Golovkin both physically and mentally.
Golovkin and Alvarez took to the ring exactly a year ago in an absolute classic which ended in a split decision draw.
It was his first defeat since the 2005 world amateur championships.
Alvarez, the new WBC, WBA and IBF middleweight champion, believes it was his extra aggression and intent which earned him the biggest win yet of an already stellar career. I wanted the knockout. "This is a very important victory to me and my country, and my country will be proud".
"I'm not going to say who won tonight because the victory belongs to Canelo according to the judges, " Golovkin said later from his dressing room. I feel satisfied because I gave a great fight.
Boxing can be a fickle game in terms of how a fighter is perceived by the mainstream majority where you're only as good as your last fight.
ESPN boxing analyst Teddy Atlas agreed.
"Under the right conditions, yes, " Golovkin said of a rematch.
Kazakh Golovkin, 36, was tentative early but clearly aware he was behind on points got more aggressive as the fight progressed.
Despite throwing less punches overrall, Canelo landed far more power shots after completely changing tactics from their 2017 meeting.
Both fighters were suitably bloodied by the end of a bruising encounter, after Alvares had somehow absorbed a series of blows to the head and chin, while Golovkin's puffy face offered proof that it had been a two-way street.
Victory was sweet for Alvarez, who had been accused of "running" during last year's first encounter by Golovkin's camp. Scores of 115-113 either way or a draw were easy conclusions to reach, meaning any talk of controversy is unwarranted.