Brian Viloria called his history with Omar Nino Romero "something that has weighed on my subconscious."

Six years after Romero handed Viloria the first professional loss of his career, Viloria exacted revenge at the Ynares Sports Arena in the Philippines, defending his WBO flyweight championship with a ninth-round TKO of Romero.

Referee Michael Ortega stopped the fight at 2 minutes, 9 seconds of the ninth round after Viloria sent Romero wobbling into the ropes with an overhand right and left uppercut combination.

Romero’s corner seemed to jump in the ring at the same time Ortega stopped the fight, signaling the end of a trilogy that Viloria had waited for for a long time.

"This wiped out a lot of my doubts in my head," the three-time world champion, who improved to 31-3 with 18 knockouts, said on TV after the bout. "I think I could have done a lot better than I did, but I’m good with this TKO."

After an even two rounds, Viloria took control in the third, landing power shots that flustered Romero, who fell to 31-5-2.

At the end of three consecutive rounds, Romero walked to the wrong corner after taking a beating from Viloria, who used the same left hook that took out Giovani Segura in his last fight last December.

Viloria continued an assault that lasted the majority of four rounds before the fight slowed and Romero seemed to start finding his rhythm.

That all changed in the ninth when Viloria came out the aggressor and staggered Romero multiple times, eating away at his face with a jab.

Romero was bleeding from a cut above his left eye that started in the fourth round.

"I established my jab a little bit better in the later rounds," Viloria said. "I think he didn’t feel the power in the last two fights because I had to lose 4 more pounds and come down in weight."

Romero handed Viloria his first professional loss in August 2006, dethroning the then-WBC light flyweight champion by unanimous decision. The two fought again three months later to a majority draw that was overturned to a no-contest after Romero failed a post-fight drug test.

After losing to Edgar Sosa following the second Romero fight, Viloria has won 12 of his last 13 bouts, including the last three at 112 pounds, where he has looked the best.

"At this weight I’ve got more power and I feel stronger," he said.