Sebastian Fundora defeated Ermal Hadribeaj with a final-round knockout to retain his World Boxing Council super welterweight crown in Las Vegas on Saturday.
The towering 6ft 6in (1.98m) Fundora used his height and reach advantages to dominate his Albanian opponent in an attritional 12-round contest.
Fundora sealed the victory just before the bell rang at the end of the 12th round, flooring Hadribeaj with a brutal left hand that sent his opponent sprawling.
Earlier, Hadribeaj had made a bright start, connecting with a series of stiff jabs in the opening round to rock Fundora.
But Fundora asserted his dominance in the second round, wobbling Hadribeaj with a left hand and forcing the Albanian onto the defensive.
Fundora continued to score regularly, and a frustrated Hardibeaj had a point deducted in the third round for excessive holding.
A flurry of Fundora uppercuts in the fifth round left the 28-year-old from California in control and he remained comfortably ahead on points over the closing rounds.
Another Hadribeaj point deduction for holding in the 11th round left the challenger needing a stoppage to have any chance of snatching victory.
But Hadribeaj's aggressive approach to the 12th round left him open, and Fundora duly pounced to floor his opponent after 2 minutes and 59 seconds of the 12th round.
Fundora improved to 25-1-1 (17 knockouts), while Hadribeaj fell to 23-1-1.