Vasyl Lomachenko stopped Jorge Linares in the 10th round on Saturday to win the WBA 'Super' world lightweight title at Madison Square Garden.
Ukraine's Lomachenko survived a sixth-round knock-down to become the fastest boxer to win three world titles in different weight divisions in just his 12th professional fight.
Lomachenko's vicious left to the body sent Linares down in the 10th to give him victory by technical knockout and end Linares' 13-fight winning streak.
The Venezuelan said he thought he could have continued and would be eager for a rematch.
At the time of the stoppage, Lomachenko was up by two points on one judge's card, Linares was up by two on another and one judge had it tied.
"I want to say thank you to Jorge Linares, he is a great fighter and he gave me one more lesson in boxing," said Lomachenko, who was sent to the canvas by a straight right to the nose late in the sixth round.
"I knew about this punch. But he is good.
"I prepared for the last few rounds, and my father told me, 'You need to go to the body'."
Among other fighters to win world titles in three divisions, Australian Jeff Fenech did so in his 20th bout while greats such as Oscar de la Hoya (22 fights) Floyd Mayweather (34) and Manny Pacquiao (41) needed even longer to achieve the feat.
"Going into this fight, we knew Loma was a huge talent," said Lomachenko's promoter, Bob Arum of Top Rank. "After this fight, we know now that he is a fighter."