Trat recorded their first win of the season on Friday night when they stunned Port 2-1 in a Thai League 1 encounter.
Port were at full strength, with the likes of Hamilton Soares, Kewin Deeromram and Bordin Phala taking the field, but still failed to produce the desired result.
The hosts were off to a great start when Lidor Cohen dashed past the Port defence to unleash an unstoppable drive and put Trat ahead in the 13th minute.
Port mounted pressure but lacked accuracy and found themselves on the receiving end once again in the four-minute first-half added time.
Trat got their second goal from Thanaset Sujarit who shot home from a narrow angle to double the home team's advantage before the break.
In the second half, the game became more excited as Port gained control and banged in their only goal of the match at the hour mark when Pakorn Prempak set up substitute Teerasak Poeiphimai for a header.
During the last 10 minutes of the match, Port were reduced to 10 men after goalkeeper Somporn Yos handled the ball outside the box and the match referee flashed the red card.
Striker Soares took over the gloves for the rest of the match.
It was Port's first loss of the season after five matches.