At Nguyen Du Gymnasium, Dang relied on defense and persistent net play to reduce his opponent's attacking threat. He remained patient in extended rallies and took advantage of errors to build a decisive margin.
Vietnam also advanced in mixed doubles, where Tran Dinh Manh and Pham Thi Khanh defeated third seeds Ashith Surya and Amrutha Pramuthesh. The home pair won 21-19, 19-21, 21-14 to secure a quarterfinal place.
Manh and Khanh will next face Chinese sixth seeds Li Hong Yi and Huang Ke Xin. The Vietnam Open is part of the BWF Super 100 circuit and runs in Ho Chi Minh City from September 8 to 13.