By CompuBox

WASHINGTON, D.C. - As the crowd swelled at the DC Armory ahead of the Ortiz-Thompson fight, Jessie Vargas (27-1, 10 KOs) and Sadam "World Kid" Ali (22-1, 13 KOs) squared off in the co-main event for the WBO Welterweight world championship.

Vargas closed the show landing 21 of 35 power punches in round nine.

Both fighters landed big power shots throughout the first half of the fight, but at the end of the eighth round, Vargas caught Ali with an overhand right that dropped the previously undefeated fighter. Ali made it out of the round but was still on shaky legs in the ninth, and Vargas continued to apply pressure until the referee jumped in and stopped the fight toward the end of the round.

With the WBC Interim Featherweight World Championshipon the line, Oscar Escandon (25-2, 17 KOs) and Robinson "Robin Hood" Castellanos (21-11, 13 KOs) waged a bloody, brutal war over seven rounds. In a back-and-forth battle, Castellanos knocked Escandon down with a sharp uppercut in the second, but Escandon beat the count, got off the deck and started breaking down Castellanos over the ensuing rounds.

Escandon opened up a cut over Castellanos' eye in the fourth and an accidental head butt led to a river of blood pouring from Castellanos' nose. At the end of the seventh, Escandon landed a body shot that knocked out Castellanos.

Luis Ortiz vs. Tony Thompson was a 12-round heavyweight fight presented by Golden Boy Promotions in association with King Kong Boxing and Warriors Boxing. Sadam Ali vs. Jessie Vargas was a 12-round fight for the vacant WBO Welterweight World Championship presented by Golden Boy Promotions in association with Top Rank, the HBO Boxing After Dark ® telecast began live at 10:00 p.m. ET/PT. Robinson Castellanos vs. Oscar Escandon was a 12-round fight for the WBC Interim Featherweight Championship and the Ring TV live stream begans at 9:00 pm. ET. The event was sponsored by Cerveza Tecate, BORN BOLD and Carmelita Chorizo.