Fresh from a 5-0 hammering of Chiangrai United last time out, the defending champions were made to work harder for their points by the league's bottom side.
Carmelo Gonzalez Jimenez was the man to get the crucial goal two minutes after the hour mark, sending Buriram two points clear at the summit.
Muang Thong United had sat behind the leaders on goal difference alone, but slipped to fourth courtesy of a 2-1 reverse at Bangkok Glass.
Goshi Okubo opened the scoring for Bangkok after just six minutes, but Datsakorn Thonglao looked to have rescued a point for Muang Thong.
However, Darko Tasevski got the winner eight minutes from time on a weekend where the remainder of the top seven all picked up points.
BEC Tero Sasana, victors over Muang Thong in their last game, climbed to second with a 2-1 win over Army United.
Chonburi sit third, level on points with Tero Sasana and two behind Buriram, after drawing 1-1 with Chiangrai United.
At the bottom, Police United moved out of the relegation zone courtesy of a goalless draw against Bangkok United.
United's third consecutive draw puts them 15th, while TOT slipped into the bottom five after their sixth defeat in a row.
Somchai Subpherm's men lost by the odd goal in five against Chainat Hornbill, with both sides having a man sent off after the break.
Fellow stugglers PTT Rayong and Air Force Central also shared the points in a result that does little to help either side's hopes of remaining in the division.
Songkhla United's clash with Osotspa was abandoned. Floodlight failure ended the game early with Songkhla leading 1-0 courtesy of Ekkachai Nuikhao's goal.
Suphanburi saw off Singhtarua 2-1, with all of the goals coming in the final 16 minutes, while Ratchaburi and Sisaket drew 0-0.