Surachat Sareepim scored the winner as BG Pathum United edged Port 1-0 at home in a Thai League 1 encounter on Sunday night.
Pathum's Raniel Santana was set up by Kritsada Kaman early in the match, but the Brazilian forward was denied by Port goalkeeper Somporn Yos.
Port saw Nobura Shimura header's go wide shortly afterwards.
The Rabbits got the goal in the 37th minute when Port midfielder Peeradol Chamratsamee made a mistake, letting Santana steal the ball and pass it on to Surachat to slip the ball between a charging Somporn's legs.
After the break, the Port came close to levelling the score through Pakorn Prempak but his shot went over the bar.
Pathum head coach Anthony Hudson said: "I am very proud of the way my team played tonight. They really played very well with lots of details.
"We didn't have much time to prepare the team, but we tried to use the tactics as effectively as possible.
"Every player showed lots of motivation and tried to control the game, especially our defenders, in the second half. Overall, it was a pleasing performance in a very exciting game."
Pathum United will play next in the Singapore Cup 2025, taking on Geylang International at Jalan Besar Stadium in Singapore on Sunday.
In the other matches on Sunday night, hosts Nakhon Pathom United picked up three points following a 2-1 victory over Khon Kaen United and Lamphun Warriors edged Sukhothai 1-0 at home.
