Chonburi, who this week announced plans to build a new 20,000-seater stadium, had cancelled out Buriram's lead at the top with a 2-0 win over Muang Thong United on Saturday.
And Buriram had to come from behind to earn a home point against Army - Javi Patino netting the equaliser after Raphael Botti had opened the scoring inside two minutes.
Chonburi's triumph over fourth-placed Muang Thong a day earlier came courtesy of second-half goals from Thiago Cunha and Pipop On-Mo.
Leandro Assumpcao marked his 100th Thai Premier League appearance by rounding off the scoring in Chiangrai United's 3-0 win over Bangkok United.
The strike represents his 32nd career goal in the competition.
BEC Tero Sasana bounced back from their defeat to TOT last time out by thumping Police United 5-2 to hold on to third spot, while Ratchaburi stayed fifth with a 1-0 win against Songkhla United.
At the other end of the table, Samut Songkhram's fate was finally sealed by a 2-0 home defeat at the hands of Osotspa.
The strugglers have been cut adrift at the bottom for some time, and the 21-point gap between themselves and safety is now too big a chasm to bridge with six matches left to play.
Air Force Central picked up a valuable point against Singhtarua to aid their own hopes of survival, while fellow strugglers PTT Rayong secured a much-needed 2-0 win against Chainat Hornbill.
In the weekend's other fixtures, Bangkok Glass hammered TOT 6-1, while Suphanburi beat Sisaket 2-0.