Nguyen Xuan Son (Rafaelson) scored one of Vietnam's two goals, while a Malaysian defender scored the other by hitting the ball into his own net.
By winning 2-0 away from home, Vietnam gains the upper hand heading into the semifinal return leg at My Dinh National Stadium in Hanoi on Wednesday evening. Coach Kim Sang-sik and his squad are well-positioned to advance to the tournament final.
The winner of the two-legged clash will take on either Thailand or Singapore in the final. Thailand won 3-1 in the first leg of their semi-final on Saturday with the return to be played in Bangkok on Tuesday.
