In 2006, Romero handed Viloria his first professional defeat on a unanimous decision and lost his WBC light flyweight title in the process.
They fought again in a rematch which saw Romero winning via majority decision in November 2006 but Romero was stripped of the title for having tested positive for methamphetamine in his post-fight urinalysis following the bout with Viloria
Romero was later suspended for nine months and fined by the Nevada State Athletic Commission after the conclusive findings.
In their third fight Sunday, Romero came in strong and very impressive in the first two rounds but Viloria made quick adjustments and he dominated the fight until the referee stopped the fight
in round 9 to protect Romero from Viloria's unrelenting assault.
After his knockout victory, Viloria, a Filipino-American
, improves his record to 31-3 (17 KOs) while Romero drops to 31-5-2 (13 KOs) with the loss.
In the undercard of the Viloria vs. Nino Romero fight, former WBC light flyweight champion Rodel Mayol scored three knockdowns over Julio Cesar Miranda and ran away with a unanimous decision
from the judges.
With the win, Mayol who is under Manny Pacquiao's MP Promotions, hopes to bag another title fight before the end of the year.