SAN ANTONIO – Pablo Rubio Jr. recorded two knockdowns of Eric Manriquez in the final round and easily won their six-round lightweight bout by unanimous decision Saturday night on the non-televised portion of the Jermell Charlo-Brian Castano undercard at AT&T Center.

The unbeaten Rubio (13-0, 4 KOs), of Whittier, California, won by scores of 60-52, 60-53 and 59-55. Manriquez (7-12-1, 3 KOs, 1 NC), a tough journeyman from Houston, tried his best to penetrate the taller, longer Rubio’s jab during the first four rounds, yet had infrequent success.

Rubio landed the flusher punches in those four rounds and built a sizable lead. In the fifth round, Rubio landed two left hooks and a right uppercut in one successful sequence that shook up Manriquez.

A right hand by Rubio knocked Manriquez off balance and into the ropes just before the fifth round ended.

Another right hand by Rubio sent Manriquez to one knee in the middle minute of the sixth round. Manriquez got up, but referee Rafael Ramos credited Rubio with another knockdown just before the final bell rang, though it looked like Rubio shoved Manriquez to the canvas.

In the previous fight Saturday night, Amed Medina barely needed two minutes to knock out Reginald Hinson.

Medina drilled Hinson with a left hook that dumped Hinson flat on his back a little less than two minutes into their bout. Hinson got to his feet, but he stumbled into the ropes and couldn’t stand up straight.

Their scheduled four-round junior lightweight fight was then stopped just 2:03 after the opening bell rang.

Medina, of Maywood, California, improved to 3-0 and recorded his third knockout. Hinson, of Rock Hill, South Carolina, lost for the first time as a pro (1-1).

Earlier Saturday night, heavyweight Roberto Zavala knocked Levi James West out of the ring to win by third-round knockout.

Zavala, of Del Rio, Texas, dropped the undersized West in the second round of West’s pro debut. West spit out his mouthpiece twice to buy time during a largely one-sided, non-televised fight.

A right hand by the 254-pound Zavala sent the 199-pound West through the ropes near a corner and onto the ring apron. Their scheduled four-rounder was stopped immediately thereafter, at 1:49 of the third round.

In the first fight Saturday, Xavier Nunez was too fast and too strong for David Alfaro throughout their junior lightweight fight.

Nunez (2-0, 2 KOs), of Corpus Christi, Texas, battered Austin’s Alfaro (1-5) and bloodied his nose until their scheduled four-rounder was stopped at 2:21 of the fourth round. Alfaro was not knocked down during their bout.

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