In 2003, Therdsak led BEC Tero Sasana to the final of the AFC Champions League against Al Ain FC in 2003.

He scored against Taejon Citizen and Shanghai Shenhua in the process and was named the 2003 AFC Champions League most valuable player.

In 2004, Therdsak secured a move to Vietnam's East Asia Bank but did not settle well due to a stomach muscle injury which kept him out for seven months.

[citation needed] Therdsak officially announced his retirement from professional football on 19 November 2017 after end of Thai League 1 season 2017 with quit of the manager job at Chonburi.

[4] He made the official managerial debut on 2 February 2016 in an AFC Champions League qualification match against Yangon United, where Chonburi won 3–2 at home after extra time.