The role of Prince Nhân Huệ in Đại Việt's army became prominent during the third invasion of Đại Việt by the Yuan Dynasty in 1287. Until then Trần Khánh Dư was the general who took charge of Trần naval base in Vân Đồn Island, the advance post of Đại Việt. At the beginning of the invasion, Prince Nhân Huệ was unable to stop the Yuan navy in Vân Đồn, a failure that Yuan troops profited to advance toward Vạn Kiếp where the principal force of Đại Việt stationed. Hence, the Retired Emperor Thánh Tông intended to imprisoned him but Trần Khánh Dư begged for several days to achieve a feat against Yuan navy before being punished. Eventually in December 1287, Prince Nhân Huệ used his remnants of navy to destroy the logistics convoy of Yuan navy in the Battle of Vân Đồn which created a favourable situation on the battlefield for the Trần Dynasty to repel the invasion. For his victory in Vân Đồn, Trần Khánh Dư was credited with the low casualties of Đại Việt during the third Mongol invasion.