In 2008, he attempted to regain the title by challenging Gerry Peñalosa who won it from Gonzalez. In the aftermath of the fight, Vorapin was defeated by an 8th round stoppage from Peñalosa on April 6, 2008 in the event "Invasion: Philippines vs. The World" at the Araneta Coliseum. Peñalosa knocked down the Thai thrice, in the 5th, 7th, and earlier in the eighth.
On September 14, 2008, Michael Domingo scored a 9th-round technical knockout victory over Ratanachai Sor Vorapin at the New Cebu Coliseum to retain the regional World Boxing Organization bantamweight title.