I'll tell you how he got it @Lunny
Now, Saensak was a beast. Unlike most Nak Muay he was renowned for his punching power. He was 140lb Raja' champ', although he lost to the masterful Poot Lorlek, an all-round technician who also had brilliant hands.
Now I need to get this out of the way. Saensak was not technical. In fact, unlike 99% of Thai's, he wasn't very technically correct at all (whilst they tend to square up they're usually well-schooled and tidy types the Thai's) and he also made no effort whatsoever to convert his style when boxing. Super slow of hand and foot. No defence whatsoever.
He had two things; one of the most ridiculous chins of all time. And two bags of gravel for hands.
To test the waters Saensak entere the South East Asian Games, where he won Gold at ten stone.
He smashed top 10 ranked Rudy Barro in his debut. On iPhone but search Saensak Muangsurin KO1 Rudy Barro on YouTube and feast your eyes on a stupendous knockout. That's how he was able to get to the top so quick he was one of the most naturally heavy handed men ever. Shit you not.
And then became the first to stop former world title challenger (to Cervantes, uploaded it on YouTube) Tetsuo 'Lion' Furuyama in his second fight.
Then he beat the hard hitting Perico Fernandez for the title. I have their rematch, only recently discovered to exist on film, on the way.
Now, WBA king Antonio Cervantes was undoubtedly the main man. However, after Wilfred Benitez beat him and moved up Cervantes was gifted the belt back by the WBA and didn't do much of note after that. I think Saensak did something ridiculous like 6 defences in a year in '77.
Mamby deserved to beat Muangsurin by all accounts. But Kim beat Muangsurin, then Mamby starched Kim so it all worked out.
Anyway, back to Saensak. Past his best, already blind in one eye he was used as a 'name' opponent for an undefeated welterweight prospect from Detroit. Check out how tough the Thai is and see what it takesto out him away. We all know how Tommy hit at 147.