The Thai men's football team got off to a bad start in the defence of their title at the Southeast Asian Games in the Philippines, losing 2-0 to Indonesia on Tuesday.
Maulana Egy Vikri opened the scoring for Indonesia after just three minutes and Ardiles Haay finished off the Thais four minutes from time in a Group B game in Manila.
The men's football tournament at the SEA Games is for under-23 players.
The War Elephants next play Brunei on Thursday.
The other teams in Group B are Vietnam, Singapore and Loas.
Tuesday's defeat came just days after the Football Association of Thailand (FAT) extended its contract with coach Akira Nishino, who oversees Thailand's senior and U23 teams.
Thailand have won the men's football title three times in a row.
Meanwhile, the Thai women's football team drew 1-1 with defending champions Vietnam in their opening Group B match.
Thailand's Taneekarn Dangda scored in the 87th minute to cancel out Van Duong's 45th minute strike.