Manzanarez scored a knockout victory over former world titleholder Gamaliel Diaz in round four at the Belasco Theatre in Los Angeles.

The 22-year-old Manzanarez improved to 34-1, 28 KOs, while Diaz drops to 40-16-1, 19 KOs.

Originally from Los Mochis, Sinaloa, Mexico and now training in Phoenix, Arizona, Manzanarez made his pro debut at the age of 15.

Although he now has 35 fights as a pro, Friday night was the first time Manzanarez fought in the U.S. as a pro.

Despite being in the twilight of his career, Diaz, who held a world title belt at 130 pounds, was the first significant test for Manzanarez.

Manzanarez had a significant height and reach advantage over Diaz. Manzanarez rained down punches onto Diaz throughout the fight, keeping Diaz mostly on the defensive.

By round four, Manzanarez began to invest in Diaz's body, as trainer Jose Benavidez advised prior to the start of the round.

The tactic paid off as Manzanarez, from a southpaw stance, landed a left hand to Diaz's body, forcing the veteran fighter to take a knee. Diaz remained on a knee as referee Raul Caiz, Sr. counted him out at 2:23.

Genaro Gamez remained unbeaten, winning a hard-fought six round unanimous decision. Gamez (4-0, 3 KOs), who came in at 138 pounds, landed the more-telling blows throughout the fight. Relying on his ring savvy, Ochoa (7-13-2, 1 KO) was able to connect with occasional right hands to the head. But Gamez displayed his pedigree during the second half of the fight, even stunning Ochoa momentarily in the sixth round. All three judges scored the bout 60-54 in favor of Gamez, who is trained by Robert Garcia.

Amateur standout Luis Feliciano won a six round unanimous decision over Angel Rodriguez. Feliciano, who was making his professional debut, controlled most of the action. Rodriguez (5-8-3, 4 KOs) who fought and lost to Jonathan Navarro two weeks ago in Los Angeles, had his moments, but never did anything to put Feliciano in danger. All three judges scored the bout in favor of Feliciano, 60-54, 60-54, and 59-55.

Junior lightweight Tenochtitlan Nava (5-0, 1 KO) won a four round unanimous decision over Thomas Smith. Nava scored with repeated right hands to the head of Smith (3-4-1 2 KOs) throughout the fight. All three judges scored the bout in favor of Nava, 40-36, 40-36, and 39-37

Junior lightweight Francisco Javier Martinez survived a second round knockdown to stop Miguel Barajas in the fourth round. Martinez, who was making his pro debut, dropped to one knee from a right cross to the top of the head by Barajas (2-2, 1 KO). Martinez pressed the action during the middle rounds, eventually stunning Barajas with a right hand to the head in round four. Martinez followed up as Barajas backed into the ropes, prompting referee Zac Young to step in and stop the bout at 2:44.

In the opening bout of the Golden Boy Promotions card, junior lightweight Jousce Gonzalez stopped Emmanuel Valadez in the opening round. Gonzalez (4-0, 4 KOs) dropped Valadez with a barrage of punches about midway through the opening round. Valadez (3-3, 3 KOs) fought back, but was dropped later in the round by a right-left combination. Referee Krysti Rosario stopped the bout at 2:42.

Francisco A. Salazar has written for Boxingscene.com since September of 2012 and has covered boxing in Southern California and abroad since 2000. Francisco also covers boxing for the Ventura County (Calif.) Star newspaper, RingTV, and Knockout Nation. He can be reached by email at santio89@yahoo.com or on Twitter at FSalazarBoxing