Saensak Muangsurin

Boonsong Mansri (Thai: บุญส่ง มั่นศรี; 13 August 1950 – 16 April 2009), known professionally as Saensak Muangsurin (Thai: แสนศักดิ์ เมืองสุรินทร์), was a Thai professional Muay Thai fighter and boxer. He was a Lumpinee Stadium super-lightweight champion in Muay Thai, as well as a WBC super-lightweight world champion in boxing. In 1975, he won a major world boxing title in his third professional fight, 241 days after his debut, which is still the record over 50 years later (later matched by Vasiliy Lomachenko in 2014 in terms of number of bouts). He is also Thailand's heaviest world boxing champion to date. Nicknamed the "World Collapsing Southpaw," he is often regarded as one of the most fearsome punchers in Muay Thai history.