TUNICA, MS - Former world champion Luis Collazo (37-7, 20 KOs) delivered an early "Knockout of the Year" candidate with a sixth-round knockout of welterweight contender Sammy Vasquez Jr. (21-2, 15 KOs) Thursday night in the main event of Premier Boxing Champions on FS1 and FOX Deportes from Horseshoe Tunica Hotel & Casino in Tunica, Mississippi.

The Brooklyn-native Collazo started slow as Vasquez Jr. looked to control the fight with his movement and jab.

The action began to pick-up in the third round as Collazo struck the first major blow of the fight, connecting on a right hand that sent Vasquez Jr. to the canvas.

Vasquez Jr. stunned Collazo early in the fourth round with an overhand left and pressed forward to initiate numerous exchanges along the ropes. Collazo was able to hold off his younger opponent and do damage with body shots and short punches in the exchanges.

After a more tactical round five, Vasquez Jr. once again pushed forward on Collazo in the hopes of getting his offense going.

The veteran Collazo was prepared for the attack and connected on a vicious right hand that put Vasquez on the mat and out for good as referee Bill Clancy halted the bout at 1:27 into the round.

"I felt like I was starting to get in my groove. He just caught me with a really great shot at the right time. I knew his big punch was the right hook. I was working on keeping my hand up to block it. I dropped it at the wrong time and he got me," Vasquez said. 

"Obviously this is going to set me back. I need to come back stronger. I hope that I can come back and fight someone that can help me move up the ranks."