Gennady Golovkin, machine-like while building a streak of 23 consecutive knockouts, became instantly mortal while narrowly escaping with a victory over an eloquent, gutty improviser in Daniel Jacobs, who won the last three rounds on all but one scorecard.
And what the challenger from Brooklyn accomplished by pushing three-belt middleweight champion Golovkin (37-0) to his limit in front of nearly 20,000 at Madison Square Garden is a reminder that the sport is best served to limit its hype and gamesmanship while relying on its natural drama.
"When you're the underdog and you go the distance and you fight back, you hurt the fighter and show what you have inside you … sometimes you lose, but it's ultimately about making fans and making a crowd-pleasing fight," said Jacobs (32-2).
"Boxing has turned out to be more of a business, certain popular fighters have something to do with that. I was in a position I had to earn my respect, had to try to bring out the best in me. Now, we move forward."
Instead of letting his manager, Al Haymon, find a way to wiggle out of fighting for the World Boxing Assn. middleweight belt when Jacobs becameGolovkin's mandatory opponent — like Canelo Alvarez did in surrendering his World Boxing Council title to the dominant Kazakhstan fighter — Jacobs embraced the concept of wanting to become the best.
He only let a shot at one of Golovkin's belts go away Saturday morning because it conflicted with his plan to win. He wanted to rehydrate and rest instead of weighing in again to meet a 170-pound limit.
Golovkin didn't admire that tactic, but he couldn't help praise the smarts Jacobs displayed in the ring, like confusing Golovkin with several turns to a southpaw style.
"There was no big punch, no lucky punch. Danny was watching. He's a very good fighter," Golovkin said. "Jacobs, from his speed and the things he did, I learned more. He has a lot of speed and power. [Early on], I was thinking, 'big drama show, big punch,' but then I had to fight very smart."
Instead of sealing another quick finish after knocking down Jacobs by belting him flush on the jaw with a fourth-round punch, the 34-year-old Golovkin was left to contend with a bigger, younger man who personifies a no-quit attitude following his comeback from bone cancer in 2011-12.
"I'm really proud of myself that I went in there and gave it all that I had, and showed some moments of grit," said Jacobs, who landed more power punches on Golovkin (144) than he took (126).
"The fight didn't go in my favor although I do really feel I won. We traded. We boxed. We entertained. That was our job.
"I had no chance, right? But I proved who I am, proved I can do whatever I can."
Golovkin landed more punches than Jacobs, 231-175, and Jacobs conceded the champion's effective jab — a 105-31 advantage — ultimately proved the difference for judges Max DeLuca (114-113), Don Trella (115-112) and Steve Weisfeld (115-112) to deliver Golovkin his 18th consecutive middleweight title win in his first 12-round fight.
"Of course, was wonderful for me during my reign," Golovkin said of his knockout streak. "It was very important to me, but during this training camp my focus was a very good quality fight. He's my best opponent. He's very smart, a very good boxer."
Golovkin and his trainer Abel Sanchez rejected the suggestion that a decline has begun, one Alvarez and his promoter, Oscar De La Hoya, have angled for by delaying a showdown they've vowed to keep in September, while Twitter and the postfight press room was abuzz on that subject.
"We hope the other fighters think that Gennady's not as dangerous anymore, so now they'll sign a contract instead of just talking about fighting," Golovkin promoter Tom Loeffler said.
Golovkin would like to fight World Boxing Organization champion Billy Joe Saunders of England in June, and then Alvarez in September. Jacobs said he can foresee a rematch between the two in 2018.
At the end of the 11th round, Jacobs closed so impressively, he pumped his chest with supreme confidence that he would end Golovkin's knockout streak and win over the judges.
He was correct on the first count, and while the judges differed, he did improve his audience.
"When I was pumping my chest, I was letting it out and showing what I had," Jacobs said. "Once you've been through everything I've been through [over] the years and get that momentum … that was me letting him know this ain't going to be the same type of fight.
"He's a man. That's what I saw in the face-off: a man who could be hurt … it wasn't what everybody made it out to be, this boogeyman."