Le Bich Phuong beat World Champion Kobayashi Miki in the women's 55kg Karatedo finals, on Thursday.
Her victory represent's Vietnam's first gold medal at the Asian Games 2010 in Guangzhou, China.
The Vietnamese martial artist sailed through the previous rounds before defeating her Japanese rival, Kobayashi, 4-3.
Also in the Karatedo event, martial artist Tran Minh Duc took the bronze in the men's 60kg category.
Runners Truong Thanh Hang and Vu Thi Huong continued to prove strong.
After winning placing second in the women's 1,500m contest on Tuesday, Hang took another silver medal in the women's 800m race on Thursday.
Huong grabbed the silver in the women's 200m event, on Thursday, after winning the bronze in the women's 100m on Monday.
Following a stunning performance, Vu Van Huyen won the bronze medal in the men's decathlon event finishing less than a hundred points behind the South Korean silver medalist.
The contestants in the decathlon competed a 100 meter race, long jump, shot-put, high jump, 400m race, 110m hurdles event discus, pole vault, javeline and 1,500m race.
So far, Vietnamese athletes have won one gold, 17 silver and 14 bronze medals and stand in the 22nd position out of 45 countries and territories.
Before the Asian Games started, the Vietnamese athletes were expected to take 4-6 gold medals and stand in the top 15.