Wilder survived a pummeling from Luis Ortiz, then knocked out the challenger in the 10th round Saturday night to retain his crown. Befitting the undefeated champion from Alabama, it was a wild affair for the final few rounds after Wilder gave Ortiz a solid lead.
Even after Wilder knocked down Ortiz in the fifth round, the bout remained in the Cuban's favor.
Then, in the seventh, Wilder was dazed and confused by Ortiz's assault. Though he never hit the canvas, he stumbled to his corner when that round ended. The end seemed near.
Instead of folding, Wilder closed the ninth with two hard rights, and then a series of vicious combinations in the 10th started Ortiz's downfall.
It was over with 55 seconds to go in the 10th after Ortiz went down for the second time in the round from a right uppercut and referee David Fields stopped it.
Wilder, 32, is 40-0 with 39 knockouts.