ATLANTA – Xander Zayas showed the type of improvement Saturday night that he promised following an uneven performance in the junior middleweight prospect’s previous fight.

Six weeks later, the hard-hitting Puerto Rican fighter picked apart a game-but-overmatched Dan Karpency for four rounds before their one-sided six-rounder was mercifully halted on the Jamel Herring-Shakur Stevenson undercard at State Farm Arena. Tom Karpency, Dan’s father and trainer, understandably stopped the beatdown because Karpency had taken a lot of punishment.

The 19-year-old Zayas, a native of San Juan who lives and trains in Sunrise, Florida, upped his record to 11-0 and recorded his eighth knockout. He will make another quick turnaround, as Zayas will face an undetermined opponent on the Vasiliy Lomachenko-Richard Commey undercard December 11 at Madison Square Garden in New York.

The 30-year-old Karpency (9-4-1, 4 KOs), of Adah, Pennsylvania, lost inside the distance for the first time in eight years as a pro.

Too fast and too powerful for Karpency, Zayas continued hammering away at his unusually tough opponent throughout a brutal fourth round for the out-gunned underdog.

Zayas unloaded an array of power punches that overwhelmed Karpency toward the end of a completely one-sided third round. For the second time in as many rounds, one of Zayas’ shots dislodged Karpency’s mouthpiece.

Stutts called for a break in the action with 1:15 to go in the second round because one of Zayas’ punches knocked out Karpency’s mouthpiece.

Zayas connected with a right hand barely 30 seconds into the first round. Karpency caught Zayas with a left hook with just under 50 seconds to go in the opening round, but Zayas affected him with a left to the body about 20 seconds later.

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