BG Pathum United pulled off a 2-1 victory at Buriram United to delay the home team's planned Thai League 1 title celebration on Saturday night.
The Thunder Castle went into the game eyeing a triumph that would assure them of a successful defence of their league crown but ended up disappointing their fans.
The Rabbits took the lead in the 10th minute of the first half when Sanchai Nontasila planted the ball into the net.
The hosts levelled the score a few minutes before the break when in-form Suphanat Mueanta put his name on the scoresheet.
Pathum United got the winner 10 minutes from time when defender Kritsada Kaman barged through the Buriram defence line and nailed it home from a few yards.
The Thunder Castle will now be hoping to wrap up the title at Ratchaburi on Saturday.
Buriram coach Osmar Loss said after the match: "We were unlucky tonight as we missed many chances. It was a tough game and before this, we had an FA Cup match that went into extra time."
Buriram will next play Bangkok United in a Thai League Cup quarter-final at True Stadium on Wednesday.
