Muang Thong stretched their unbeaten league run to 13 matches on Saturday, but Dragan Talajic's men could only muster a 2-2 draw at Ratchaburi.
Wuttichai Tathong had put the visitors ahead in the 28th minute, only for Genki Nagasato to level for the hosts 10 minutes before the break.
It got better for Ratchaburi nine minutes after the restart when Heberty Fernandes put them ahead, yet the lead proved short-lived as a minute later Tossapol Lated restored parity.
Muang Thong's draw meant defending champions Buriram could have moved within one point of top spot if they won at relegation-threatened PTT Rayong.
That scenario looked on the cards when Theeraton Bunmathan put the visitors ahead after quarter of an hour, but Pichet In-bang levelled for PTT in the second half to give the strugglers a much needed point.
Also on Saturday, Songkhla United missed the change to escape the drop zone after being held to a 1-1 draw at home to Army United, lowly Police United gained a 2-2 draw with Sisaket, despite a brace from Tatree Sing-Ha for the visitors and Saranyu Intaraat's late sending off. Chiangrai United also beat Suphanburi 2-0.
On Sunday, Chonburi moved third and level on points with Buriram courtesy of a comfortable 2-0 win at Bangkok Glass.
Goals in each half from Thiago Cunha and Chakrit Buathong proved enough for Masahiro Wada's side to pick up three points at the LEO Stadium and rack up a fifth straight top-flight win.
BEC Tero Sasana could also have moved to 47 points, but they were held to a frustrating 0-0 draw at home to relegation-threatened Air Force United and have now gone three league games without a win.
In other matches, rock-bottom Samut Songkhram's miserable season continued in a 3-0 home defeat to Singhtarua, Chainat Hornbill failed to move out of the bottom five after a 1-1 draw with Bangkok United and Osotspa were 3-1 winners on their visit to TOT.
