Buriram United continued their good run with a 2-0 home win against 10-man Trat in Thai League 1 on Tuesday night.
At Chang Arena, Supachai Chaided opened the scoring for the Thunder Castle after 24 minutes and Suphanat Mueanta added the second eight minutes from time.
Trat's Junior Lopes was sent off just before half-time for tripping Piyaphol Panichakul, who was heading into the penalty area.
But with 10 men, the visitors frustrated the hosts in the second half before Suphanat broke their defence.
Buriram are now three points clear of Port, who travel to PT Prachuap on Wednesday.
In last night's other game, hosts Muang Thong United were stunned 2-1 by Police Tero.
Dragan Boskovic scored from the spot to give Police the lead after 19 minutes and Teerathep Winothai made it 2-0 just before the interval.
Sorawit Panthong scored a consolation goal for the Kirins in the dying moments.
The win is a huge boost for Police in their fight for survival as they are now nine points above the relegation zone.
Muang Thong remain fourth, four points behind Port.
In Wednesday's action, third-placed Port visit Prachuap, hoping to earn back-to-back victories after securing a 3-1 triumph against Rayong which ended their five-match winless streak.
Also, Bangkok United host Nakhon Ratchasima, Rayong are at home to Ratchaburi and Suphanburi face Samut Prakan.
On Thursday, runaway leaders BG Pathum United need a win against Sukhothai to wrap up the title with six matches to spare.
