Chris Eubank Jr delivered a grandstand finish to beat Conor Benn by unanimous decision at the Tottenham Hotspur Stadium.
Eubank took a unanimous decision, all three judges scoring 116-112 in his favour, after a tremendous 12-round, back-and-forth clash.
The sons were picking up the rivalry of their famous fathers, Chris Eubank Sr and Nigel Benn.
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That saga took a new turn when earlier in the evening when, totally unexpectedly, Eubank Senior, without warning, arrived at the stadium alongside his son.
The estrangement between the pair had been in the public eye after Conor Benn's jibes in the build up to the fight and Eubank's own unguarded speech about that fractured relationship had stunned their final press conference.
The roar in the stadium reached a fever pitch of extraordinary intensity when Eubanks senior and junior ringwalked together.
In another echo of his father, Junior of course had to vault the top rope to land on the ring canvas, throwing a blur of punches through the air as the electric noise howled all around him.
His father followed him into the ring and embraced both Conor and Nigel Benn.
The roar of the crowd rose up yet again as the first bell tolled. Eubank came out behind his jab, his advantage in size apparent as he kept Benn at bay with his left.
But there was a moment within the opening round when Benn backed up a double jab with a flush cross, a full bodied right that Eubank had to take flush.
Benn managed to connect in the second round too. His left landed stiffly, twice jolting Eubank with a weight that he appeared to feel.
Benn was dangerous early on. He let his right burst over and it crashed into Eubank's temple and jaw.
He was taking those attacks in the third and fourth rounds. But Benn, with bustling dynamism, was getting through.
Eubank was willing to trade with him. He tagged Benn with his right uppercut and swept it through once again, bouncing Benn's head upward.
In the sixth round Eubank met him with a jab, but Benn managed to get inside and let spiteful left hooks sink in.
Eubank popped another solid jab in but his right cross just glanced off Benn.
He stepped off breathing heavy for a moment and the pace of the fight slackened for a moment.
In the seventh round Benn charged on to a huge right uppercut, a blow that drew a gasp from the crowd.
A long left propelled Benn back. Benn was leaking punches and Eubank helped himself to a three-shot combination.
As Benn cantered forward once more, Eubank greeted him with a curving right.
Grimly determined, Benn just fought his way forward, only for the Eubank cross to snag him high on the head.
In the eighth round though Benn kept himself in touch with a storm of wild punches. Benn though paused to regroup and Eubank jabbed low, before clocking him with a left hook.
But drawn into an exchange, Eubank looked to hold. His legs seemed to weaken and the crowd bellowed as the fighters leaned on to each other hurling punches with just their arms.
Eubank was cut by his right eye in the ninth round. It was a battle for him to contain Benn. Both men, at times had to pause, just to suck in air. But they still found the reserves to go again. Eubank slung wide hooks that caught Benn's jaw in the 10th round.
Defence was abandoned for a moment as they just heaved their punches into each other.
Eubank finished that round with Benn backed up on the ropes, just pouring in punches. The power in them drained away as he tired, but Benn didn't find a reply.
They stood in the centre of the ring. Their feet no longer moving, as they tried to extricate their arms from clinches and let their barrages of punches carrying on flowing.
It was sapping, draining effort and neither man, at that late stage, looked likely to shift the other. They were however taking the pain.
But Eubank hammered through that. He was unrelenting. He kept throwing and his left hook sank in with full force to buckle Benn's legs.
The uppercut hit home too and Benn's eyes were glassy as Eubank carried on his attack. Benn's instinct was to fight back and he did, a left hook striking Eubank's body hard. But Eubank delivered a grandstand finish in that last round and secured the unanimous decision win.
Fractious build up
Eubank Jr and Benn's rivalry had grown more bitter in the build up to this fight. They had originally been due to box in 2022, at a catchweight, but that bout was eventually called off when the results of Benn's failed drug tests emerged.
Only in November, when Benn's provisional suspension was lifted without appeal from the British Boxing Board of Control and UKAD, was he permitted to box in his home country.
The build up to this fight was fractious. Benn and Eubank were separated in altercations before and after the latter's previous bout. At their own announcement press conference, Eubank had cracked an egg across Benn's head, a reference to a claim form the WBC which Benn later distanced himself from that excessive consumption of eggs had led to the anti-doping violation.
Benn was moving up from welterweight for this fight at middleweight, but the deal did involve a rehydration clause preventing Eubank from being more than 10lbs over the limit on the morning of the fight.
Eubank met that stipulation, but had been half an ounce over 160lbs at the official weigh in, a miscalculation that saw him suffer a financial penalty, reportedly in excess of £300,000.
But this victory for Eubank will be the ultimate gratification, his biggest win on the most important night of his career.
'We upheld the family name'
"I knew I was capable of that. I just needed someone to bring it out of me," Eubank said. "I didn't expect Conor to be the guy to do that. I didn't know he had that in him, I thought I would break him early.
"I underestimated him, I didn't prepare for a fight like that," Eubank continued. "The fact our fathers fought years ago brought out a different spirit and I am happy to have my father with me.
"He needed to be here. All this is because of him. We upheld the family name - onwards and upwards."
