Nguyen's impressive performance earned him a total of 447points, falling just short of Aik Soe Lin of Myanmar, who secured the goldmedal with 449 points. Phupakorn Wongthanachet of Thailand claimed the bronzewith 437 points.
The morning's events also saw several athletes from Vietnamqualify for the finals in athletics, and swimming.
In swimming, Vietnam sent two young athletes, Nguyen Thuy Hienand Pham Thi Van, to the final of the women's 100m freestyle.
Their seniors, Le Thu Thuy and Vo Thi My Tien, qualified forthe women's 400m freestyle. Nguyen Quang Thuan and Tran Hung Nguyen willcompete in the men's 400m individual medley final.
Nguyen Huu Kim Son and defending Nguyen Huy Hoang receivedbyes to compete in the men's 1.500m freestyle in the evening.
In athletics, Ngan Ngoc Nghia will be present in the men's 200m, while newbies Tran Thi Yen Nhi and Kha Thanh Trucwill run in the women's 200m.
Also, Vietnam's hope for medals in the triathloncollapsed in the morning.
Both men's and women's representatives, Lam Quang Nhat andNguyen Thi Kim Cuong, could not finish their race.
Nhat quit when he was in the running stage because ofexhaustion, while Cuong was ruled out by an injury during cycling.
After a medical check, boxer Nguyen Thi Tam announced badnews for supporters. She had a torn ligament of the left knee and now faces along spell out of the ring.
The world silver medalist was expected to win SEA Gamesgold three times in a row, lost via technical knock-out in her first matchagainst Jutamas Jitpong of Thailand in the women's 54kg after suffering herinjury.
The injury might prevent her from participating in theSeptember Asian Games in China and qualifications for the Paris Olympics./.