The Vietnamese pair defeated compatriots Cao Dai Duong and Le Khanh Duy Tu 6-2, 6-3 in the men’s double’s category.
Earlier, Vu Artem and Miguel Diaz of the US beat Vietnamese pair Huynh Thinh and Tu Nhut Ngoc 6-0, 6-3 in a mixed-doubles match.
The hosts’ top player, Ly Hoang Nam, will play his first singles match today against Diaz. Nam is the No 2 seed in the tournament.
In other matches, national champion Pham Minh Tuan will take on Michael Look of Australia while Vu Artem will play No 8 Arjun Kadhe of India.
In the latest world rankings released yesterday, Vietnam have five representatives.
Nam has the highest position at No 522, 30 steps higher than last week, after his semi-final result at the Vietnam F1 event two weeks ago.
Trinh Linh Giang is No 1,365 while Nguyen Hoang Thien is at No 1,867.
Young talent Nguyen Van Phuong, 16, and Vietnamese champion Tuan make their ATP ranking debut after winning the F1 event’s first round. Phuong is at 1,608 and Tuan is ranked 1,711.
Phuong is not laying the F3 tournament as he is playing in the US, while Giang has withdrawn on account of illness.