Holders BG Pathum United delayed Buriram United's Thai League 1 victory celebration with a 1-0 win over the runaway leaders on Sunday night.
Sarach Yooyen scored the winner after 13 minutes as the Rabbits won at Chang Arena for the second season in a row.
Buriram are nine points ahead of Pathum with four games remaining.
In another game, Port secured a rare win in the second half of the season when they came from two goals down to beat Nakhon Ratchasima 3-2.
After a scoreless first half at PAT Stadium, the visitors raced to a 2-0 lead early in the second with goals from Abdulhafiz Bueraheng and Shintaro Shimizu in the 58th and 62nd minute respectively.
But Port made it 2-2 a few minutes later thanks to goals by David Rochela and Teerasak Poeiphimai before Bordin Phala hit the winner in the 78th minute.
It was Port's only second win since the season resumed in January.
Meanwhile, English coach Kevin Blackwell suffered a losing start to his spell at Nakhon Ratchasima, who are just two points above the drop zone.
It was reported that Nakhon Ratchasima chairman Worawi Makudi handpicked Blackwell to help the Swat Cats stay up in the top flight. "It's not over till it's over," Blackwell said after the loss.