Former champions Buriram United assured themselves of a second-place finish in Thai League 1 with an impressive 4-0 victory over visiting PT Prachuap on Sunday night.
Buriram's Samuel Rosa reacts after scoring a goal against PT Prachuap on Sunday night.
The Thunder Castle will now represent Thailand in the 2022 AFC Champions League qualifying play-offs.
They can also make the group stage of the event along with this year's league champions BG Pathum United by winning the FA Cup final of which will be played on April 11.
Eight T1 teams are in contention for this year's FA Cup title.
The result also left Port needing a win in their last match against Nakhon Ratchasima on Sunday to avoid being dependent on the outcome of Chiang Rai United's two remaining games to secure the third and last ACL spot available through the top league.
Samuel Rosa scored two goals in a space of six minutes -- his second coming from the spot after the hosts were awarded a penalty in the 26th minute. Myanmar striker Ang Thu scored the third just before the break.
Maicon Marques added his name to scoresheet to complete the rout with a strike in the 89th minute.
True Bangkok United fired three goals in the second half to record a 4-1 home victory over relegated Rayong.
The capital side saw Manuel Tom Birh net the only goal of the first half a little after the 30-minute mark before switching into a higher gear after the break.
Nattawut Suksum (57th minute), Heberty Fernandes (60th) and Anon Amornlertsak (67th) hit the mark to put Bangkok United 4-0 ahead.
Rayong's only goal came of the game in injury time through Anusorn Jaipetch.
Another relegated side, Trat, fared no better last night as they were defeated 3-1 by hosts Samut Prakan.
Also last night, Police Tero were held to a goalless draw at home by Nakhon Ratchasima.