Britain's Nathan Cleverly retained his WBO light-heavyweight title with an eighth-round stoppage win over American Shawn Hawk in Los Angeles.
The 25-year-old displayed superior skills and hand speed to record his fourth successful defence of the belt, his first in the United States.
He took some heavy shots but knocked Hawk down twice in round seven, with a left hook in the next ending the fight.
Cleverly's 12th win inside the distance extends his unbeaten record to 25.
It was the first time that 28-year-old Hawk had failed to go the distance in his 26 professional bouts.
He was only confirmed as Cleverly's challenger on Monday after original opponent Ryan Coyne was forced out due a legal dispute with promoter Don King.
Cleverly's belt was carried to the ring by his fellow Welshman Sir Tom Jones and American actor Mickey Rourke at the Staples Center, the home of the Los Angeles Lakers NBA team.
From the outset Cleverly's hand speed exposed Hawk's lack of lateral movement and made him a prime candidate for the left uppercut to the head.
The American, who was a cruiserweight until 2010, began the second with a solid left hook to the body, but Cleverly responded by sending some sharp head shots on the ropes.
In round four the champion was caught flush by a firm straight right and he took some further return fire in the next, despite peppering Hawk's chin with combinations from right uppercut to left hook.
Having jostled his opponent with a left-right assault in the sixth, Cleverly unleashed a pair of right hooks in the next to send him gasping to the canvas, and Hawk was down again before the end of the round after another flurry of punches.
A thudding left hook to the kidneys left Hawk sagging, and referee Tony Crebs ended proceedings after one minute and 53 seconds of the eighth round as a concluding right sent Hawk down and the towel was thrown into the ring by the American's camp.