The Da Viets abandoned their capital city. Then attacked the Mongol supply lines. The Mongol horses had no grass. Lots of guerilla attacks. Traps. Disease. More food supply destruction. Then a second attack with similar results.  Wood stakes  tipped with iron driven into river beds. Mongols entered at high tide. At low tide the spikes punctured the Mongol boats. Then Viets counter attacked. Mongols were crushed. 1288.

https://youtu.be/djKoP1MJ6Ug
How Vietnam Crushed Kublai Khan's Mongol War Machine