The Thai cyclist won the 50km race around Xuan Huong Lake in Da Lat City in a time of 1:14.41.
Lee Euheen of the Republic of Korea (RoK)’s Samyang and Yoshikawa Miho of Japan were the runners-up.
Lee Joohee of the RoK holds the green jersey award as the best sprinter with 28 points.
Despite finishing in 12th in this stage, Nguyen Thi Thu Mai of Gao Hat Ngoc Troi An Giang retains the yellow jersey for the best overall time of 9:31.49 after four stages.
In the team rankings, Biwase Binh Duong lead, followed by Gao Hat Ngoc Troi An Giang and the Netherlands.
Today, cyclists will compete in the fifth stage from Nha Trang to Phan Rang City, lasting 120km.
The event features nearly 140 cyclists from nine foreign teams and nine domestic.