Thai League 1 leaders BG Pathum United, reduced to 10 men for the bigger part of the second half, hit four unanswered goals past Suphanburi on Saturday night to mount pressure on second-placed Port.
Port, who have a game in hand, take on Ratchaburi on Sunday evening, needing a win at their home ground to keep their title challenge on track.
Veteran defender Andres Tunes struck just two minutes after the start and Supasak Sarapee doubled the home team's advantage 20 minutes later.
Surachart Sareephim's red card for elbowing a Suphanburi player left Pathum depleted for over half an hour in the second half.
However, Surachart's absence did not slow down the leaders and they picked up two more goals as Chatree Chimtale fired home in the 79th minute and Tunez bagged his second of the game during the six-minute injury time.
Former champions Buriram United made a big leap last night as they took over the fifth spot on points difference, edging hosts True Bangkok United 2-1.
Bangkok United found themselves on the receiving end when Jakkaphan Kaewprom put the Thunder Castle ahead at the hour mark. The hosts equalised through Vander Luis three minutes later but conceded from a set-piece in the 73rd minute with Renato Kelic heading home the winner.
Hosts Samut Prakan City went on a scoring spree for a 4-1 victory over neighbouring Chonburi.
Barros Tardeli was the home team's hero, claiming a hat-trick in the match which helped Samut Prakan leapfrog their opponents into eighth place on goal difference.
Tardeli was on target in the 14th, 45th and 77th minutes with Chakkit Laptrakul providing the other goal for the hosts on 67 minutes, three minutes after Channarong Promsrikaew had pulled one back for the Sharks.