Thai League 1 pacesetters BG Pathum United extended their lead to nine points after beating Nakhon Ratchasima 2-0 on Friday night.
Brazilian defender Victor Cardozo scored in each half for the visitors.
With the win, the Rabbits have 35 points, nine ahead of champions Chiang Rai United, who are playing in the Champions League in Qatar.
Port are third on 25 points but have played two games fewer than BG.
At Nakhon Ratchasima, the hosts missed a golden chance to take the lead when they were awarded a penalty in the 40th minute.
Leandro Assumpcao's 'Panenka penalty kick' was easily saved by BG goalkeeper Chatchai Butprom.
Deep into injury time, the Swat Cats conceded a penalty and Cardozo made no mistake from the spot.
Cardozo was on target again in the 68th minute as the Rabbits remain unbeaten.
Meanwhile, in-form Port are in confident mood ahead of their clash at Chonburi on Saturday.
Third-ranked Port have enjoyed an impressive run since Sarawut Treephan replaced Jadet Meelarp as coach in September.
Under Sarawut, the FA Cup champions have won six successive matches including five in the league.
"Our players' confidence has been boosted by recent results. Every player has a chance to show his potential," Sarawut told a press conference.
However, he was cautious about his team's chance against Chonburi, who will be without Herlison Caion after the Brazilian striker was suspended.
"We cannot make any mistake," Sarawut said."We still have tough matches to come against Muang Thong, Ratchaburi and Chiang Rai.
"We have won many games and people expect more from us. This puts pressure on the coach and the team to keep winning."
Chonburi coach Sasom Pobprasert said: "It will be a tough match but we are fearless at home where we often get good results."
He said the absence of Caion would not affect the Sharks.