Los Angeles (AFP) - Jarrett Hurd of the United States stopped Britain's Jason Welborn in the fourth round to retain his WBA, IBF and IBO light middleweight titles.
The 28-year-old from Maryland on Saturday survived an early onslaught from Welborn before going on the offensive midway through the fourth.
After driving Welborn into the middle of the ring, Hurd connected with a vicious right to the Englishman's torso which sent him sinking to the floor.
Welborn, who earlier had Hurd in trouble in the third, was unable to beat the count as referee Lou Moret called the contest to a halt.
Hurd improved to 23-0 with 16 wins inside the distance following the victory at the Staples Center, part of the undercard for the WBC heavyweight clash between Deontay Wilder and Tyson Fury.
Hurd had looked to be in complete control in the opening two rounds, coolly slipping away from Welborn's punches and finding his range with a tidy jab.
However Welborn responded gamely in the third, backing Hurd into the corner and wobbling the champion with a left hook which smashed through his defenses.
Encouraged, Welborn started the fourth brightly but had no answer when Hurd finally landed to the body.