By Gabriel TanFollow @@gabetan13
It took the Chilean, on loan from Union Espanola, just five minutes to open his account although there was a touch of fortune involved as Muangthong's Phichitphong Choeichiu, in a desperate attempt to prevent Kai Hirano from gaining possession on the edge of the area, inadvertently headed the ball into his path.
But after the ball smashed off his foot and looped into the air, there was no doubting the quality of the finish as Bustos timed his volley to perfection and unleashed a ferocious left-footed strike past a hapless Weera Koedpudsa.
Early on in the second half, Muangthong had a decent shout for a penalty turned down after star striker Teerasil Dangda was barged over by Suree Sukha inside the area, but the defending Thai Premier League champions' hopes of victory were then handed a blow in the 60th minute when defender left-back Mongkol Namnuad was sent off after picking up his second booking.
With the numerical advantage, the Thunder Castle began to dominate proceedings and looked to have doubled their lead shortly after, only for the referee to disallow an effort from Theerathon Bunmathan.
Nonetheless, they were not be denied and wrapped up the victory seven minutes from time when Bustos netted his second, applying the finishing touches to a sweeping counterattack, handing the first piece of silverware of the new season to last year's FA Cup and League Cup champions.
Both sides are next in action on Tuesday as they begin their bids for continental glory in the AFC Champions League, with the Twin Qilins at home to Jeonbuk Hyundai Motors, while Buriram travel to Japan to take on Vegalta Sendai.
Image courtesy of Buriram United