Once Gennady Golovkin connects with an opponent’s jaw, he’s accustomed to finishing the job. But even though he floored Daniel Jacobs in the fourth round of their middleweight title unification bout Saturday night at Madison Square Garden, there was Jacobs still on his feet and exulting at full throat after ending the 11th round with a flurry of power punches that had a full house of 19,939 fans roaring with him.

“When I pumped my chest, I was grinning at him and showing bravado,” Jacobs said. “I was in the zone. I was letting him know this wasn’t going to be easy.”

Jacobs won the final round on two of three cards, but Golovkin escaped with a close unanimous decision that marked the first time in his career that he was forced to go 12 rounds and that ended his streak of 23 straight knockouts. He added Jacobs’ WBA title to the other three belts he owns from the WBC, IBF and IBO, but he also came away with great respect for Jacobs.

“Yes, he’s my best opponent,” Golovkin said. “Very smart, don’t panic, don’t lose control . . . It was a very good fight, very good experience. Daniel is a world champion.”

Golovkin admitted disappointment at seeing the end of his string of knockouts, dating back to his last decision nine years ago in an eight-round bout. “It’s life,” Golovkin said. “Of course, it’s very important because it is my record. Daniel broke my record.”

Judges Don Trella and Steve Weisfeld favored Golovkin, 115-112, and Max DeLuca scored it 114-113. According to CompuBox, Golovkin (37-0, 33 KOs) landed more jabs, 105-31, but Jacobs (32-2, 29 KOs) landed more power shots at 144-126. The stats showed Jacobs came on strong by landing more power punches from rounds six through 11.

advertisement | advertise on newsday

Abel Sanchez, who trains Golovkin, was surprised by the resiliency Jacobs showed after the knockdown. “Danny wasn’t going to roll over,” Sanchez said. “He looked at Gennady and said, ‘C’mon, let’s go.’ That’s when we knew we were in for a long night.”

Jacobs said he did enough to win or to at least get a draw. Asked how he handled Golovkin’s power, Jacobs said, “It wasn’t what everybody made it out to be. He’s not this boogeyman, this KO artist. Even when he knocked me down, it really didn’t hurt me. I knew I’d be the bigger man.”

At fight time, Golovkin weighed 170 pounds, just 10 over the middleweight limit. Jacobs declined to be weighed but said he was about 175. He credited former WBO light welterweight champion Chris Algieri of Greenlawn with designing a nutrition program that had him in peak condition.

“Chris Algieri helped me out,” Jacobs said. “He made sure I wasn’t drained.”

Jacobs asked for a rematch, and Golovkin said it’s possible. But Golovkin’s camp wants him to fight in June in his native Kazakhstan. It’s possible he will meet WBO champ Billy Joe Saunders, who has the only belt Golovkin is missing.

@NewsdaySports

“It is my dream fight,” said Golovkin, ignoring momentarily the prospect of facing Saul [Canelo] Alvarez in a mega-fight in September. “My goal is to win all the belts.”