Vietnam, seeking to regain the title from Thailand, had to wait till the 58th minute for their opening goal, courtesy of Nguyen Hai Long.

That, however, opened the floodgates as Nguyen Tien Linh doubled their advantage five minutes later with Nguyen Van Toan adding the third in the 69th minute.

Van Vi Nguyen netted the fourth in the 82nd minute with Laos pulling one back through Bounphachan Bounkong's stoppage time penalty.

Indonesia, aiming to win the title after having emerged runners-up six times, found the going tough against a resolute Myanmar.

After bombarding the Myanmar goalmouth, Indonesia were finally rewarded in the 76th minute when Zin Nyi Nyi Aung turned the ball into his own net.

Up next for Indonesia are Laos on Thursday while Myanmar will meet the Philippines. Group A action on Wednesday will see Singapore meeting Cambodia while Malaysia will host Timor-Leste.