By Ryan Burton

Newly crowned WBA Interim Featherweight Champion Claudio Marrero (22-1, 16 KOs) shocked previously unbeaten Carlos Zambrano (26-1, 12 KOs) with a first round knockout in the main event of Premier Boxing Champions on FS1 and FOX Deportes, Saturday night from Sam's Town Live in Las Vegas.

"There's so many emotions going through my head right now, that I still can't wrap how it feels to be a champion now," said Marrero. "I won't let it distract me, because I'll fight whoever is the best in my weight class. I knew what kind of fighter I was going up against and I knew what had to be done. I was hungry"

The fight ended abruptly as Marrero of Santo Domingo, Dominican Republic threw a rock solid straight left hand that sent Lima, Peru's Zambrano to the canvas, rendering him unable to stand and referee Vic Drakulich waved off the bout at 1:30 of the one and only round. Marrero extended a seven-fight win streak.

"After being inactive for a year, of course my timing was a little off I am not happy at all with my performance," said Zambrano. "This is a fight that was long awaited and I know Marrero has been eyeing me for a while, so it's just unfortunate the way things ended.

"I need to come back to the states and find sparring partners who can really help get me to the level that I want to be," continued Zambrano. "For my record to be beaten at this point, its just really disappointing I have no other words to describe it."

The co-main event of the FS1 and FOX Deportes telecast ended in a sixth round TKO by hungry middleweight Nathaniel Gallimore (18-1-1, 15 KOs) of Kingston, Jamaica over Jeison Rosario (12-1, 9 KOs) of Santo Domingo, Dominican Republic.Both fighters came out swinging in the first round with Rosario taking it on all three judge's scorecards.  Rosario, who had never gone past the fourth round started to slow down in the fifth as Gallimore took over.

"I came into the fight confident then at some point something just happened, my body started to slow down," said Rosario. "I got a little tired and I started to fight a little sloppy. My plan is to go back and begin working on my jab consistently, that was my weakness during throughout the fight."

Gallimore came out of the corner in the sixth round determined to end the fight and succeeded. He dropped Rosario, but the Dominican rose to his feet, only to be dropped by a hard upper cut. In the end, it was a left hook that sent Rosario to the canvas for a third and final time as referee Jay Nady waved off the fight at 2:15 of the sixth round.