Horn, cut and badly hurt, was on the verge of being stopped in the ninth round when he roared back and dropped Zerafa twice to get back into a fight he had been dominating.
Fighting with a savage intensity totally opposite to his mild-mannered demeanour outside the ring, Horn, 32, rekindled the same passion and power that had propelled him to his epic victory over Manny Pacquiao two years ago at Suncorp Stadium.
He took off to a flying start against Zerafa in the opening round and kept his foot on the accelerator all night.
While Zerafa had talked a good game in the fiery lead-up to the fight, Horn’s fists spoke the loudest when it mattered most. He won by scores of 94-94, 98-90 and 97-92.
Zerafa, 27, came into the ring under an Aboriginal flag in honour of his friend Dwight Ritchie, the former Australian champ who died sparring him on November 9.
Horn immediately set about shattering his confidence throwing big shots from the opening bell.
"The Hornet’s back. It’s a great feeling. I’m going to enjoy Christmas and talk about what’s next with my family, whether I fight again,’’ Horn said.
"There could be a world title opportunity for me so we’ll see what happens.
"Michael deserves all the respect in the world. I know he said a lot in the lead-up to this but he’s a good guy, I reckon, and he put in a champion performance.’’
Zerafa, who had stopped Horn in nine brutal rounds in Bendigo on August 31, made no excuses.
"Jeff was the better man on the night but I’ll be back. I’m only 27 years old. Congratulations to Jeff and his team and Merry Christmas to everyone.’’
In round 1 Horn was cut beside his left eye but landed a big right.
Horn was trying to take off Zerafa's head with every punch in the early going and Zerafa’s confidence evaporated.
In Round 2 Horn continued the assault. Referee John Cauchi warned Horn for hitting to the back of the head but the Queensland had Zerafa on the back foot as chants of "HORNET HORNET’’ became louder and louder.
Zerafa landed a good left hook in Round 3 but he came back strong. Zerafa was starting to find his range and connected with a right hand but Horn was a much different fighter to what we saw in Bendigo.
He was a much more difficult target and in Round 4 his jab pumped again into Zerafa’s startled face. Zerafa began lunging with punches and Horn was landing brutal counters.
Zerafa’s trainer was giving his corner advice by text message from his Melbourne home but Zerafa had to cop the punches by himself.
Horn, wearing a pair of Zerafa’s boxing gloves after a last minute change of equipment, was setting a frenetic pace. In Round 5 he was warned again for hitting behind the head but he had Zerafa rattled. In close Horn was doing a lot of damage.
In Rounds 6 and 7 he kept the pressure on as Zerafa missed wildly trying to nail him.
In the end, Horn’s calm composure saved the day.
As Zerafa found new legs and new punches in the ninth round, Horn was under siege and badly hurt. His father Jeff Snr, climbed out of his seat five rows from ringside and headed towards his corner as though ready to stop the fight.
But just as he did, Horn nailed Zerafa right on the chin. Zerafa went down, got back up and then staggered into another bomb.
He went down again and it was the moment that sealed Horn’s victory.
As Zerafa tried to turn it around again in the 10th Horn was one step ahead and when the final bell sounded the crowd erupted in delight for the hometown hero.
Horn was inspired by his Stretton Boxing Club teammates.
After two knockout losses to start his career, Horn’s younger brother Ben Horn, 30 won his first pro fight outpointing Billy Holland from Toowoomba in a four-round welterweight bout.
And Horn’s southpaw teammate Andrew Hunt scored a unanimous eight-round decision over former world title challenger Czar Amonsot, a heavy punching Filipino from Melbourne.
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Updates
What is next on the horizon for these two fighters?
They've split their two fights so far. Two stunning fights, too.
Tonight's an instant classic.
Is there a trilogy in the mix? The punters would certainly demand it.
Or is a showdown with Tim Tszyu what will pay the bills for Jeff Horn?
The judges scores are through and Jeff Horn is the champion!
Incredibly one of the judges ruled it a draw, but the other two give it to Horn 90-98, 92-97.
The ref is absolutely covered in blood. Both fighters are empty.
Zerafa's camp was fuming throughout the 10th round, but the defeated fighter goes to Horn to raise his hand in victory. A class act.
What an incredible fight that was.
Horn dancing around here, he knows he has the points behind him. He just needs to hold on.
Both fighters bleeding profusely, as Zerafa looks for a knockout. It's his only path to victory.
Zerafa goes right to the death – searching for anything, any clean looks. But he can't do it.
Horn hangs on. That will be enough, surely.
His camp charges in to congratulate him.
A brutal flurry to start the ninth round as Zerafa takes his corner's advice and throws a barrage of clean hits.
This is savage stuff. Horn cannot protect himself as Zerafa is rocking him badly.
The mind goes back to Bendigo where Glenn Rushton was heavily criticised for not throwing in the towel.
But MY WORD. Absoltuely remarkable comeback from Horn who rocks Zerafa with a savage right hook – and then another!
Zerafa goes down! Twice! Double knockdown after Horn had been absolutely buried for the first.
What a remarkable turnaround. Blood everywhere. One round to go.
Zerafa is throwing all the pressure at Horne in these final rounds. The challenger has almost nothing left in the tank but he's getting by on guts alone.
He takes that round, but he's still behind on the count.
Zerafa knows he has three rounds to stop this from going to a points decision.
"Put the pressure on – he's HURT. We want to stop him. We want to knock him out," Zerafa is told by his corner.
This is a terrific fight.
Excellent right hand from Horn early in the round, but Zerafa has the better of the action thereafter.
The fatigue is starting to set in for Horn, whose punches have become even more wild and loose.
Has he got 3 more rounds in him? Zerafa needs to charge now.
This is a terrific fight.
Excellent right hand from Horn early in the round, but Zerafa has the better of the action thereafter.
The fatigue is starting to set in for Horn, whose punches have become even more wild and loose.
Has he got 3 more rounds in him? Zerafa needs to charge now.
Both fighters are slowing down a touch – fair enough, given the frenetic pace so far – but more punches are landing.
Horn rocks Zerafa with a powerful right hook, but Zerafa responds with a huge right hand to the body.
Both fighters very much in the wars right now. They'll have to dig deep in the final four rounds.
Again, looks like a Horn round. 4-2? 5-1? Several rounds on a knife edge.
The cut above Zerafa's eye is really opening up – and it's been deemed to have come from a head clash. That's one to keep an eye on.
Tough round to call, but Horn has opened up a cut over the right eye of Zerafa.
Horn is absolutely charging here, but Zerafa dominated the middle of that round.
Could be Horn 4-1 – but Horn is being regularly warned about hitting behind the head. he needs to be careful there or he'll be docked points.
Zerafa needs to wake up before it's too late.
A close round, but Jeff Horn has possibly gone ahead 3-1 with just relentless pressure.
He lands several shots to the head of Zerafa as the power strategy pays dividends.
Zerafa needs to correct things and quickly because Horn is pushing the pace.
Can he keep it up for 10 rounds? He said he was fitter and stronger… he's putting that to the test.