LAS VEGAS -- Former pound-for-pound king Roman "Chocolatito" Gonzalez announced his return following a two-fight losing streak with a thunderous bang.

Fighting in front of an empty T-Mobile Arena to kick off the Canelo Alvarez-Gennady Golovkin II pay-per-view main card on Saturday, Gonzalez landed a jaw-dropping combination that removed heavy underdog Moises Fuentes of his senses via fifth-round knockout in their junior bantamweight bout.

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Gonzalez (47-2, 39 KOs), who dominated the action bout from start to finish, packaged a flush left hook with a brutal overhand right that turned Flores' chin stage right and caused him to violently hit the back of his head on the canvas on the way down. Referee Robert Byrd immediately waved off the fight at 1:44 of Round 5.

The win was a much-needed one for the 31-year-old Gonzalez, a native of Nicaragua, who dramatically dropped from his status as Pound for Pound king following two defeats in 2017 to 115-pound champion Srisaket Sor Rungvisai, including a knockout so scary in their rematch that many wondered whether Gonzalez would ever be the same, let alone return.

"I'm very thankful for this opportunity. It's a great comeback to be on the Canelo vs. Golovkin card. I can't wait because I am a step closer to becoming a world champion," Gonzalez said. "When he hit the floor, I got very worried for him and I panicked, and when he regained consciousness and I prayed for him and I told him that I hope god blesses him, his family, and his career. I asked for him to forgive me, because this is the job that we chose and that I didn't mean to hurt him."

Although the former four-division champion absorbed more clean counter right hands than he needed to in order to walk Fuentes down and finish him, he did so in dominant fashion. Gonzalez cut Fuentes (25-6-1, 14 KOs) in Round 2 above his right eye and outlanded him by a margin of 145 to 47, according to CompuBox. Gonzalez also connected on 47 percent of his power shots.

Fuentes, 32, a native of Mexico, suffered his fourth defeat over his last five bouts and is a former titleholder at 108 pounds.

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