Michael Conlan got revenge over Vladimir Nikitin after an unanimous points victory over the Russian in New York.
Bad blood has festered between Conlan and Nikitin since their hugely controversial meeting at the 2016 Olympic Games in Rio de Janeiro.
Conlan was denied a medal after the fight was scored in the Russian’s favour with the Irish fighter slamming officials before retiring from amateur boxing on the spot.
Now two years into his professional career, featherweight Conlan extended his record to 13-0 win a disciplined performance against his old rival at Madison Square Garden.
The judges' scorecards read 98-92, 99-91 and 100-90 in Conlan's favour.
"I have no ill-feeling to Vladimir. It wasn't personal. But I needed to get one back,” Conlan said.
"That fight could have been very emotional for me after everything that happened. I had to remain calm. We worked on it in training and it worked tonight."
Elsewhere on the card, Teofimo Lopez was crowned the new IBF lightweight champion at just 22, stopping Richard Commey in the second round. Lopez floored the Ghanaian with a devastating right that the now former champion never recovered from. Brooklyn-born Lopez waded in for the finish to become a world champion in just his 15th pro fight.
Terence Crawford meanwhile retained his WBO welterweight title with an impressive ninth round knockout win over Egidijus Kavaliauskas.