NEW YORK – Ivan Baranchyk began working his way back into the 140-pound championship mix Saturday night.

The former IBF junior welterweight champion became the first fighter to knock out veteran Gabriel Bracero, who lost by fourth-round technical knockout on the Gennadiy Golovkin-Sergiy Derevyanchenko undercard at Madison Square Garden. Bracero bravely tried trading with Baranchyk, but Baranchyk is a much harder puncher and wasn’t affected by Bracero’s shots.

Baranchyk (20-1, 13 KOs) knocked down Bracero (25-4-1, 6 KOs) with 1:44 left in the fourth round after viciously connecting with a left hook to the body, and then a right hand to the head. A battered, bloodied Bracero got up, but his corner men instructed referee Arthur Mercante Jr. to stop their scheduled 10-round fight at 1:30 of the fourth.

Bracero, 38, hadn’t been knocked out in 29 professional fights before Baranchyk stopped him. His first three losses each were 10-round, unanimous-decision defeats.

This marked Baranchyk’s first fight since Scotland’s Josh Taylor dropped him twice, beat him by unanimous decision and took the IBF 140-pound crown from him May 18 in Glasgow. Taylor (15-0, 12 KOs) advanced to the final of the World Boxing Super Series’ 140-pound tournament by beating Baranchyk.

Taylor is scheduled to face New Orleans’ Regis Prograis (24-0, 20 KOs), the WBA champion, in the WBSS’ 140-pound championship match October 26 at O2 Arena in London.

Baranchyk belted Bracero with a left hook that buzzed him about 40 seconds into the fourth round. The aggressive ex-champion from Belarus sensed the end was near and applied pressure to a fading Bracero before blasting him with the aforementioned left hook to the body and right hand to the side of his head.

A left hook by Baranchyk moved Bracero backward just before the midway mark of the third round. They traded hard right hands toward the end of the third round.

Bracero hit Baranchyk after the bell, which made an animated Mercante warn him as Bracero went back to his corner.

Baranchyk wobbled Bracero with a left hook 40 seconds into the second round. About 20 seconds later, Bracero lifted up Baranchyk by his legs and threw him to the canvas.

Mercante warned both boxers for rough tactics before allowing the action to resume.

Later in the second, Baranchyk blasted Bracero with two left hooks as Bracero backed into the ropes. Bracero moved out of that vulnerable position before Baranchyk could finish him off.

Bracero drilled Baranchyk with a straight right hand toward the end of the first round. An overanxious Baranchyk threw a left hook so hard at Bracero that he fell to the canvas just before the bell to end that first round.

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