Vietnam lost 0-3 to China in a game where the opponent were superior in every aspect, with contributions from the injury of key defender Nguyen Hieu Minh and a red card of Pham Ly Duc.
China will face Japan in the final while Vietnam will meet South Korea in the third-place playoff.
Vietnam are having their most convincing performance in the history of the tournament, being one of the rare two teams to win all four matches (along with Japan). These include strong opponents such as Jordan, Saudi Arabia (group stage) and the UAE (quarterfinals).
Unlike their historic journey in 2018, coach Kim Sang-sik's team surprised fans with their physical fitness, alongside their spirit, courage and discipline in their playing style.
For China, this is the first time in the U23 Asian Cup that they have advanced beyond the group stage and reached the semifinals. China have surprisingly remained undefeated and have not conceded a single goal. They achieved three 0-0 draws in regular time and extra time against Iraq, Thailand (group stage), and Uzbekistan (quarter-finals), setting a new record in the tournament.