By FOX Sports staff
Following a goalless first half, the deadlock was broken in the Spanish defender Manuel Redondo found the back of the net for the Thunder Castle.
Despite their best efforts, Muangthong were just unable to break down the opposition defence and their hopes of a comeback were effectively ended five minutes from time when they had goalkeeper Witsanusak Kaewkruang sent off.
Standing in between Buriram are a second consecutive FA Cup title are Bangkok Glass, who booked their place in the final after defeating Police United 5-2 at the Rajamangala Stadium.
The Glass Rabbits took the lead in the 18th minute when Teeratep Winothai netted, but their opponents hit back just seven minutes later through a strike from Paitoon Nontadee.
But eager to justify his recall to the Thailand national team, Teeratep struck again five minutes after the half-hour mark tp restore his side's lead, before Police were dealt a blow when Sompob Nilwong received his marching orders in the 55th minute.
A minute after the hour mark, Bangkok Glass further extended their lead through a Flavien Michelini effort and it was 4-1 two minutes later when Korakod Wiriyaudomsiri got in on the act.
The result was all but secured when Goran Jerkovic weighed in with a fifth three minutes from time, although Police did manage another consolation effort when Pinyo Inpinit scored deep into injury-time.
Wednesday's Thai FA Cup Semi-final Results
Buriram United 1-0 Muangthong United
Bangkok Glass 5-2 Police United
Image courtesy of Buriram United FC