Thailand coach Mano Polking says he is impressed by the U23 side and the talent of a number of players.
The Thai junior team secured a place in the 2022 AFC U23 Asian Cup in Uzbekistan after finishing second in their qualifying group in Mongolia last week.
They had two draws -- 1-1 with the hosts and 0-0 with Malaysia -- and a 3-0 win over Laos in the tournament.
Polking, 45, has not yet started his job after being appointed national team coach in September.
He is in isolation for seven days after arriving in Thailand on Oct 30.
"Congratulations. Mission accomplished. We are in Uzbekistan. Space for improvement for sure but let's take the positives. We didn't have all players available, especially up front," the Brazilian-German coach wrote in a social media post.
"We conceded just one single goal. We didn't lose a single match and we can build players like Jaturapat Satthum, Anusak Jaipetch, Thanawat Suengchitthawon, Jonathan Khemdee, Jakkit Phalapol and Korrawit Tasa just to mention some players. Enjoy the moment, come back home and we continue to work hard for the tuture."
Thailand's Jonathan Khemdee. PR
Polking will be in charge of the War Elephants at the AFF Suzuki Cup to be held in Singapore from Dec 5-Jan 1.
The Thais are in Group A with Singapore, Myanmar, the Philippines and Brunei or Timor Leste.
Midfielder Thanawat, of English Premier League side Leicester City, has already played for Thailand's senior team.
Thai-Danish defender Jonathan of Denmark's Odense BK, who represented Thailand for the first time in the tournament in Mongolia, has also won praise from U23 coach Worrawoot Srimaka and critics.
Worrawoot said a number of his players are good enough to play for the full national team, particularly Thanawat, Jonathan and midfielder Benjamin Davis of English League One side Oxford United.
He said Thanawat has "everything" while Jonathan is a "modern" defender.