Vietnam's football authorities have launched an investigation into the humiliating loss of the home side to Malaysia last night at My Dinh Stadium, which led to the country being knocked out of the ASEAN Football Federation Suzuki Cup.

"No one understands what happened on the field," said the chairman of the Vietnam Football Federation, Le Hung Dung. "Watching the entire journey of Vietnam soccer team against Laos, Philippines until the semifinal against Malaysia , we saw a very good team."

Vietnamese players (red) all cried after losing 4-2 to Malaysia at My Dinh Stadium on December 11.

The investigation will examine whether there was any indication of match fixing by those gambling on the outcome of the match, which Vietnam lost 4-2 against Malaysia, despite a 2-1 win in Selangor, Malaysia, on Sunday.

The loss knocked Vietnam out of the AFF Cup and relegated it to third place, along with the Philippines.

"The players' performance was very different to what they did before," said the VFF chairman.

"The team's defeat on December 11 night seems very suspicious," Dung said. "Are they really that bad or not?

"The first leg played very well. I will ask the police to investigate. I want to know whether it was just a matter of their poor performance."

Vietnam coach Toshyia Miura accepted responsibility for the surprise loss, in front of a sold-out 40,000 crowd. He said the team lost because it lacked experience, but all the players were fired up going into the game. A series of penalty and tactical blunders let Malaysia drive in four goals in the first half, which the home side struggled to redeem.

Miura said that if the VFF wanted an explanation for the loss, he was ready to explain what happened.