Adrien Broner claimed a stoppage victory over Khabib Allakhverdiev to win the vacant WBA super-lightweight title at US Bank Arena in Cincinnati.
The controversial American (31-2-KO23) insisted in the build up to the bout that he was a changed man having attracted widespread criticism for his brash talk outside the ring and recent failure to back up his words in it.
But Broner was in fine fettle against the Russian, setting the pace of the fight from the off.
The 26-year-old, returning to the ring for the first time since his points decision loss to Shawn Porter in June, picked up the pace in the fourth and fifth rounds. Broner, looking the far superior fighter, landed with left jabs and overhand rights and continued to land with the jab in the sixth, leaving Allakhverdiev visibly marked.
Broner continued on the offensive, dominating the seventh, eighth and ninth rounds with Allakhverdiev (19-2-KO9) unable to deal with a flurry of body and head punches.
Allakhverdiev, who came into the fight after more than a year out of the ring, failed to recover and was left dazed in the 11th round with a further flurry of punches from Broner, growing in confidence as the rounds wore on.
A bombardment of unanswered punches from Broner with less than 39 seconds left in the final round was enough for referee Harvey Dock Jr to stop the fight. The victory ensured Broner claimed a world title in a fourth weight division, adding to previous super-featherweight, lightweight and welterweight championships.