Thai boxer Wanheng Menayothin grabbed his 51st straight victory Wednesday in a long but lopsided bout against a fighter from the Philippines, defending his WBC title and surpassing the undefeated record of boxing legend Floyd Mayweather Jr.

The 105-pound minimumweight champion, nicknamed the "dwarf giant" for his compact build and heavy hitting style, won on points after a bruising 12 rounds against Pedro Taduran in the Thai city of Nakhon Sawan.

Wanheng started strong, landing several hard rights in the early rounds that seemed to daze Taduran and signal a quick route.

But the 21-year-old southpaw from the Philippines lived up to his alias "Rattle Snake", enduring the abuse and biting back in the fifth round with a flurry of punches.

The brief comeback was put down as Wanheng kept his composure in the second half of the bout, delivering clean hits that left Taduran visibly tired.

Wanheng, 32, shot to unlikely fighting fame in May when he dispatched Panamanian Leroy Estrada, equaling "Money" Mayweather's win streak.

All three judges scored in his favor after the final round.

Wanheng's record-busting quest has generated buzz in Thailand and in boxing media outlets.

But it has also been shrugged off as a statistical quirk because of the two very different careers of the famous, flashy American and the soft-spoken Thai.

Wanheng has fought undistinguished rivals on home turf while Mayweather defeated some of the sport's all-time greats including Manny Pacquiao and Oscar de la Hoya.

Mayweather's fights also come with huge purses, like the $100 million on offer when he was teased from retirement last year to take on MMA star Conor McGregor.

Wanheng's legal name is Chayaphon Moonsri but he also fights under the alias "Five-Star Grilled Chicken" due to a sponsorship deal with a Thai food company.

His latest win brings him level with Mexican flyweight Ricardo Lopez, who retired with 51 wins, one draw and no losses.