Myanmar lead the group ahead of Vietnam on goal difference while Malaysia will have to beat Myanmar in their final preliminary tie if they are to advance to the semi-finals.
Laos 1-3 Myanmar
Vientiane: Laos, who were looking to avoid a third straight defeat in Group A, took the lead after seven minutes through Phouthone Innalay who drilled his effort from the top of the box.
Laos were the better side in the first half and they kept their opponents at bay with goalkeeper Outthilath Nammakhoth making a fine save in the 41st minute to maintain their slim advantage.
Myanmar, however, hit back just before the break with Aung Thu levelling the score from the edge of the box.
Myanmar almost took the lead in the 51st minute through Lwin Moe Aung but Nammakhoth held his nerve to deny them.
Htet Phyo Wai finally found a way past Nammakhoth after winning possession at the edge of the area before firing a stunning strike to give Myanmar the lead in the 72nd minute.
Maung Maung Lwin then added another in the 85th minute to give Myanmar the win and three valuable points and top spot in the group on goal difference.
Vietnam 2-0 Malaysia
Hanoi: Both teams came into match undefeated and Vietnam, backed by a partisan crowd, struck in the 11th minute as they capitalised on poor Malaysian defending with Nguyen Cong Phuong slotting the ball past goalkeeper Khairul Fahmi Che Mat.
Malaysia, the 2010 champions, had the lion's share of possession in the second half but could not break down their opponents who doubled their advantage in the 60th minute to the delight of the fans at the My Dinh National Stadium.
Vietnam took advantage of another Malaysian defensive lapse in the 60th minute as Nguyen Anh Duc beat the offside trap to fire the second goal past Khairul Fahmi as Park Hang-seo's side sealed a convincing win.
Photos: Asean Football Federation