by David P. Greisman, live from ringside in Washington, D.C.

Carlos Cuadras defended his 115-pound world title with a sixth-round technical knockout of late replacement Marvin Mabait. Cuadras looked like he scored a knockdown toward the end of the fourth, but referee Eddie Claudio ruled that the fighters’ feet had been tangled.

Cuadras made up for it in the fifth when Claudio called a knockdown, ruling that the ropes had held Mabait up during the sequence. In the sixth, Cuadras floored Mabait early with a right hand. Mabait got up at the count of four but was soon sent back down, and this time Claudio had seen enough.

The end came 36 seconds into the round.

Mabait filled in for former lineal flyweight champion Sonny Boy Jaro, who was reportedly not allowed to enter the United States due to issues receiving his visa.

Cuadras, a 26-year-old from Mexico, moves to 31-0-1 with 25 KOs. He won the World Boxing Council belt in May with a technical decision over Srisaket Sor Rungvisai in a bout that ended after a clash of heads opened a cut on Cuadras. He defended it this past September in another cut-shortend bout, a four-round technical draw with Jose Salgado.

Mabait, a 26-year-old from the Philippines, is now 19-3-2 with 13 KOs. He has lost two in a row and three of his last six.

- Former female flyweight titleholder Ava Knight dominated Guadalupe “Lupita” Martinez en route to a shutout decision, winning 100-90 on all three scorecards.

There were no knockdowns, though Knight did stun Martinez in the second round with a left hook followed by a right hand, and Knight continued to patiently punish her overmatched opponent down the stretch.

Knight, 26, of Chico, California, is now 13-2-3 with 5 KOs. She lost a 115-pound title fight to Ana Maria Torres back in 2009, drew with 118-pound titleholder Kaliesha West in 2011 and went on to win a belt at 112 pounds later that year, dropping it prior to a bout with fellow titleholder Mariana Juarez in 2012. She also challenged for a 108-pound title in 2013, losing a decision to Ibeth Zamora Silva.

Martinez, a 22-year-old from Mexico, is now 7-8 with 3 KOs. She’s lost world title shots at 115 pounds against Debora Anahi Dionicius in 2013 and at 108 pounds against Naoko Shibata this past March.

- In the opening bout of this three-fight card, Antoine Douglas won a unanimous decision over Don Mouton, with all three judges seeing the fight 60-54. Douglas, a 22-year-old middleweight prospect from Burke, Virginia, moves to 16-0-1 with 10 KOs. Mouton, 36, of Houston, falls to 14-9-1 with 12 KOs and has dropped five of his past seven, including decisions against Anthony Dirrell and Badou Jack, plus a first-round stoppage against Gilberto Ramirez Sanchez.

Pick up a copy of David’s book, “Fighting Words: The Heart and Heartbreak of Boxing,” at http://bit.ly/fightingwordsamazon or internationally at http://bit.ly/fightingwordsworldwide . Send questions/comments via email at fightingwords1@gmail.com