Wong, ranked a lowly 74th in the world, managed a total of 238.30 to claim the win.

In what is already being talked about as one of the biggest upsets in the history of the regional event, world number one Hoang could only manage a score of 234.10.

It came after he became the first ever Vietnamese Olympic champion after winning this event in Rio de Janeiro last year.

Myanmar’s Kyaw Swar Win bagged the bronze with a 214.80 total.

"It is a fantastic feeling to beat an Olympic champion for the title," said the winner.

"This is for all Malaysians and also my family, and not forgetting my grandfather, who turned up for the first time here.

"This will give me the motivation to attain greater things. 

"My aim is to make an impact in next year's Gold Coast Commonwealth Games and at the Asian Games in Indonesia."

Rhythmic gymnast Koi Sie Yan was another home winner.

She claimed individual all-around spoils at the Malaysian International Trade and Exhibition Centre with a score of 63.150 points.

The 18-year-old amassed 16.600 points in hoop, 15.600 in the ball execution, 15.250 in clubs and 15.700 in ribbon.

It followed victory in the group event yesterday.

Team-mate Amy Kwan Dict Weng took silver with a total score of 60.100 points.

Singapore's Tong Kah Mun bagged the bronze with 52.900.

Malaysia have also set-up a men's football final with defending champions Thailand on Tuesday (August 29) after defeating Indonesia 1-0.

Thailand defeated Myanmar 1-0 in the other last-four clash.