Edwin De Los Santos was determined Friday night to not leave it to the judges again on “ShoBox.”

The Dominican southpaw knocked Luis Acosta unconscious with a left hand early in the second round of their scheduled eight-round lightweight bout in Deadwood, South Dakota. Referee Mark Nelson stopped their fight immediately after De Los Santos’ devastating left hand knocked Acosta cold and left him flat on his back 45 seconds into the second round.

The official time of the stoppage was 48 seconds of the second round in a bout Showtime aired as the co-feature of a “ShoBox: The New Generation” tripleheader from Deadwood Mountain Grand Hotel.

De Los Santos (14-1, 13 KOs) was the first fighter Houston’s Acosta (12-1, 11 KOs) faced in 13 pro bouts who had a winning record.

Santo Domingo’s De Los Santos suffered his first professional defeat just 63 days earlier to William Foster III (14-0, 9 KOs). De Los Santos lost that eight-rounder by split decision January 7 at Caribe Royale Resort in Orlando, Florida.

Showtime also televised Foster-De Los Santos as part of its “ShoBox” prospect series.

A right hook by De Los Santos made Acosta spin away from him and touch the canvas with both gloves, which counted as a knockdown with 1:20 to go in the first round. Acosta caught De Los Santos with a right hand with just under 20 seconds to go in the opening round, but De Los Santos landed a straight left with 10 seconds left in it.

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