The 26-year-old South African defeated Chainoi Worawut in the final of the 57 kg tournament via decision after a three-round war with the Thai.
Gomba reached the final after defeating a Chinese opponent with an elbow in the second round.
The standout fighter, who has fought in Bangkok's famed Rajadamnern Stadium, trains out of Phuket's AKA Thailand in Rawai/Nai Harn area. A video of his fight against Chainoi can be seen here.
The event was organised by the Thai government, WMC and International Federation of Muay Thai Amateur to commemorate the coronation day of Somdet PhraSanphet VII, known as the father of Muay Thai.