"It's good that I can still stand," 59-year-old Payap Tongchuen joked after donning gloves and trunks and going two rounds with Direk Tungfang in a boxing ring set up for the occasion in front of the parliament building in Bangkok.
The referee declared the fighters - both former professional boxers - joint victors.
Spectators thought Direk, 64, from Nonthaburi province just north of Bangkok, outclassed his opponent from the eastern province of Sa Kaeo, knocking him down once. Both men sit in the upper house where lawmakers have no party affiliation.
"The aim is to market Thai boxing, as Muay Thai at the international level," said Direk. "It is also to campaign for the younger generations to maintain this traditional sport."
Muay Thai, as Thai kickboxing is known, is the national sport and its popularity has been growing worldwide. Fighters employ punches, kicks and elbow and knee strikes against their opponents.
The event was set up by the Senate's sports committee, and the opening demonstration on the day's card was between a pair of 8-year-old boys.