PT Prachuap will play Thai League 1 leaders Buriram United in the League Cup final.
Prachuap stunned defending champions Chiang Rai United in a penalty shoot-out 4-3 in the semi-finals at Boonyachinda Stadium on Wednesday night.
It will be the club's first appearance in the final of the tournament.
Buriram marched into the final with a comfortable 2-0 victory over Nongbua Pitchaya on the same day.
The final will be played at Muang Thong's SCG stadium on Sept 28.
Both teams were locked 2-2 after 90 minutes and 3-3 after extra-time.
Jean Philippe Mendy put Prachuap 3-2 ahead on 99 minutes but a free-kick from Peerapong Pichitchotirat in the 105th minute forced the shoot-out.
Nishino to pick players
Thailand head coach Akira Nishino will name the list of probables for the World Cup squad on Sunday.
Thirty players will be selected to participate in a training camp before the final 23 will be announced later for the first two Group G matches against Vietnam and Indonesia.
The other teams in the group are United Arab Emirates and Malaysia.
Thailand will host Vietnam on Sept 5 at Thammasat stadium before travelling to Indonesia five days later.
Meanwhile there will be no video assistant referee (VAR) during Asia/Oceania's qualifying round for the 2022 World Cup next month, according to the Asian Football Confederation (AFC).
The system, however, will likely be used during the AFC U23 Championship in Thailand next year, said Patit Supaphong, deputy secretary of the Football Association of Thailand.