Michael Coffie knocked out another undefeated heavyweight on national television Saturday night.

The late-developing prospect dropped Darmani Rock twice in the third round and scored another impressive knockout in a fight FOX broadcast as part of the Caleb Plant-Caleb Truax undercard from Shrine Auditorium & Expo Hall in Los Angeles. Referee Jack Reiss stopped the action 59 seconds into the third round of a scheduled 10-rounder.

Brooklyn’s Coffie upped his record to 12-0 and produced his ninth knockout. The 34-year-old Coffie took up boxing at the late age of 29, after serving eight years as a U.S. Marine.

Philadelphia’s Rock (17-1, 12 KOs) was supposed to test Coffie, but Coffie tore through an opponent who was a decorated amateur.

Coffie cracked Rock with a quick left uppercut that floored him just 23 seconds into the third round. Rock barely beat Reiss’ count and continued, though not for long.

Another left hook by Coffie, which landed to the top of Rock’s head, sent Rock to the canvas again with 2:09 remaining in that third round. Rock slowly attempted to reach his feet again, but Reiss stopped counting at seven and ended their fight.

Rock connected with a right to Coffie’s body just after the halfway mark of the second round. Coffie landed a left up top a few seconds later that made Rock hold him.

Rock took a knee with 52 seconds to go in the second round, seemingly after taking a low left from Coffie. Reis did not call that a knockdown, though.

Coffie and Rock were cautious throughout the first round. They mostly threw jabs as they attempted to feel each other out in those opening three minutes.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.