By Lerpong Amsa-ngiam
The home team lost the goal in the 17th minute when Anirudh Thapa converted on a pass from Adil Ahmed Khan. Thapa also scored a goal for India in the Asian Cup against Thailand in January which also ended in the Indian favour 4-1.
Thailand launched a series of raids in the second half but their attempts proved to no avail due to better teamwork and solid defence of the visitors.
The defeat added salt to Thai wound after they lost to arch-rivals Vietnam 0-1 in the previous game on Wednesday.
However, captain Teerasil Dangda, after missing the clash with Vietnam, finally made his appearance in the game and won his 100th cap. He became the fifth Thai to achieve the milestone after Piyapong Pue-on , Kiatisuk Senamuang, Totchtawan Sripan and Datsakorn Thonglao.
Dismal results in the friendly tournament will affect the destiny of acting coach Sirisak Yodyathai as the Football Association of Thailand may look for a new permanent coach.
Later in the day, Curacao beat Vietnam in a penalty shoot-out 5-4 after a 1-1 at normal time to claim the 47th King's Cup title.