By ESPNSTAR.com staff
The defeat comes just six days after Buriram were beaten 4-3 by second-placed Chonburi at the Thunder Castle Stadium, and means they are now eight points behind leaders Muangthong United having played the same amount of games.
And while Attaphol Puspakom's men could have been forgiven for falling to the high-flying Sharks last Sunday, they will certainly have no excuses for losing to a side who are currently in 14th place and battling against relegation.
Yet, it was Thai Port who took the lead after just nine minutes when a freekick from Kiatcharoen Ruangpan was only half-cleared straight to defender Woo Hyun, who lashed home a fierce left-footed drive into the bottom corner.
Five minutes later, the Port Lions doubled their advantage when Sarawut Kongjaroen latched onto a clever through-ball by Alex da Costa and fired past Sivaruck Tedsungnoen into the top corner.
With the hosts now happy to sit back and defend their two-goal lead, Buriram enjoyed plenty of possession for much of the second half but ultimately struggled to break down a resilient Thai Port defence.
It wasn't until the third minute of injury-time when they handed an excellent chance to score after Suriya Domtaisong was tripped by Pongpipat Kumnuan inside the area.
Theeraton Bunmathan stepped up to the spot and clinically sent Wanlop Saechio the wrong way with his penalty, but it proved too little too late as the Thunder Castle were condemned to a shock defeat.