She said the team will receive a reward of 5 million baht (US$144,285) if they reach the semi-finals, The Nation reported.
The reward was announced after Thailand thrashed Brunei 5-0 in their opening match on Tuesday.
Their possession in the game was 80%, with 33 attempts and 16 shots on goal.
However, Lamsan, nicknamed Madame Pang, said the team needs to improve in converting chances.
"Our finishing skill was not good and we need to improve that," she said after the game. "Fortunately, we fought until the end and scored three more goals."
In the first half, Thailand led Brunei 2-0 thanks to goals by Bordin Phala and Teerasil Dangda. The second half saw Thailand struggling with their attack before scoring three more goals in the last five minutes with Peeradon Chamratsamee’s double and an own goal. The win helped Thailand take the top seat of group A after the first round.
Meanwhile, Vietnam, Thailand’s main challenger, crushed Laos 6-0 on Wednesday to take the lead in Group B. The goals were scored by six different players.
Thailand will play the Philippines on December 26 while Vietnam will face Malaysia a day later.
Vietnam won the tournament in 2018, their second time, while Thailand have won it six times, including the previous edition.