Wanheng Menayothin dethroned WBC minimumweight champion Oswaldo Novoa in Chon Buri yesterday.
Wanheng Menayothin, right, in action against Oswaldo Novoa.
The Thai, the top contender in the 105-pound division, won the title after the Mexican quit after the ninth round in the mandatory fight.
The Maha Sarakham native, who is the country's 49th world champion, extended his unbeaten record to 36 wins with 12 knockouts while Novoa, who was in his second title defence, suffered his fifth loss against 14 wins and one draw.
In the first eight rounds, it was a close encounter with the Thai leading 79-73, 77-75 and 76-76.
In the ninth round, Wanheng knocked down Novoa who then refused to come out of his corner for the 10th round of the 12-round bout.
Wanheng's manager Piyarat Wachirarattanawongse said that it was beyond his expectation to see Wanheng win the fight by a knockout.
"I expected Wanheng to win on points but he did it in style,'' said Piyarat.
"We are pleased to see him win the title after a seven-year wait.''
Piyarat said his 29-year-old boxer could become a great champion in the 105-pound division.
"He has power and skill,'' he said.
Wanheng is likely to defend his title in January or February, Piyarat said.