For the second time in a row, Australia thwarted Vietnam's chances of reaching the final of the ASEAN Under-19 football championships in HCM City on July 28.

Mohammad Mustafa Amini, Mathew Allan Leckie, Benjamin Halloran, Eli Babalj each scored a goal to help Australia beat Vietnam 4-1 – the same margin of defeat as last time.

Vietnam 's only goal came from Nguyen Van Thanh after a skilful chip in the second half.

The defeat meant Vietnam finished fourth out of four teams on two points after two draws. They will play against third-ranked Republic of Korea for third-place on July 30.

The win means Australia topped the group with seven points. They will face second-ranked Thailand in the final at 6.30pm on July 30 at Thong Nhat stadium. Thailand earned three points from three draws.

"Our players lost concentration and conceded early goals and everything went the wrong way," Trieu Quang Ha, Vietnam 's head coach, said at the post-match press conference.

Meanwhile, a jubilant Australian coach said: "We qualified for the final after Thailand and the RoK drew in the earlier match but we still wanted to play a good game. Early goals made it easier for us but we were more consistent than Vietnam."

Contrary to the tactics Vietnam used in the match against the RoK, the home side took the game to Australia, a move that proved fatal.

Taken full advantage of Vietnamese defenders' confusion, Mohammad Mustafa Amini burst into the box beating keeper Tran Buu Ngoc just two minutes into the game.

Mathew Allan Leckie headed home from a corner on the right wing to double the score in the 15th minute.

Vietnam changed their style after going two-nil down and created some clear chances, but Le Quoc Phuong, Thanh, and Nguyen Thanh Hung failed to capitalise on the opportunities presented.

In a counter-attack four minutes from the interval, Benjamin Halloran scored from a low pass from Ngoc to make it 3-0.

Australia rested some players in the second half, allowing the home side to gain more possession, which eventually resulted in substitute Eli Babalj heading a winner for Vietnam./.