MIAMI GARDENS, Florida – Marc Castro continued making up for lost time Saturday night.

The promising prospect from Fresno, California, knocked John Moraga to the canvas once in the first round and twice during the second round. Referee Frank Gentile halted the action at 2:29 of the second round, as soon as Moraga went down for the third time in their scheduled four-round junior lightweight fight on the Canelo Alvarez-Avni Yildirim undercard at Hard Rock Stadium.

After having his pro debut delayed several times due to COVID-19 and an ankle injury, the 21-year-old Castro (2-0, 2 KOs) produced his second knockout in 10 weeks. He knocked out Luis Javier Valdez in the third round of his first professional fight December 19 on the Alvarez-Callum Smith undercard at Alamodome in San Antonio.

Phoenix’s Moraga (1-3, 1 KO) was a late replacement during fight week because Castro’s original opponent contracted COVID-19.

Following a strong first round, Castro sent Moraga to the canvas for the second time with a hard right hand. Moraga got up again and tried to fend off an aggressive Castro.

Castro’s left uppercut, which was set up by a right hand, sent Moraga to the canvas for the third and final time with just over 30 seconds to go in the second round. Gentile quickly stepped in to stop the fight after that third knockdown.

Castro continued to hit Moraga with jabs, overhand rights up top and body shots during the second round.

A stiff jab by Castro caught Moraga off guard and knocked him down less than 10 seconds into their fight. Moraga seemed more surprised than hurt and got right to his feet.

Castro connected with several power shots later in the first round, but Moraga remained on his feet.

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