Vietnam's AFF Cup defence ended with a whimper as they were held to a goalless draw by Thailand at the Kailang National Stadium in Singapore on December 26, losing the semi-final 2-0 on aggregate.
Vietnam become the former champions of the AFF Suzuki Cup after losing 0-2 on aggregate against Thailand.
Coach Park Hang-seo made five changes to his line-up compared to the first leg, with Nguyen Cong Phuong, Nguyen Tuan Anh, Vu Van Thanh and Nguyen Van Toan dropped in favour of Nguyen Tien Linh, Ha Đuc Chinh, Phan Van Duc and Ho Tan Tai.The line-up was similar to how Vietnam played in the second half of the last game, with the exception of Bui Tien Dung replacing the injured Do Duy Manh.
Knowing they needed to redress a two-goal deficit, Vietnam flew out of the blocks and put pressure on Chatchai Budprom's goal from the off.
Their first real chance came in the 3rd minute, when Nguyen Quang Hai had a shot on goal but it was caught easily by Chatchai.
Twenty minutes later, Quang Hai slipped Tan Tai through on goal, but the 24-year-old blasted his shot from a difficult position over the bar.
In the 27th minute, Tien Linh was almost through on goal after a great ball over the top from Quang Hai, but Chatchai raced out of his goal to clear the danger, injuring himself in the process. He was replaced by Siwarak Tedsungnoen.
Vietnam's best chance of the half came in injury time when Nguyen Phong Hong Duy cut the ball back to Quang Hai, but he fired over the bar from just inside the box.
Thailand almost made coach Park's men pay for their profligacy in the final seconds of the first half, but goalkeeper Tran Nguyên Manh was equal to Theerathon Bunmathan's powerful shot.
Both coaches made changes in the second half, and Thailand used theirs to effectively kill off the match.
Thailand's Mano Polking brought on tall centre-back Elias Dolah and switched to a defensive 3-5-2, while coach Park went all in, bringing on Van Toan and Cong Phuong for Hong Duy and Ha Duc Chinh, and switched Vietnam to a back-four formation.
Thailand's changes neutralised the Vietnamese players, who seemed to run out of ideas and resorted to pumping the ball long at every opportunity, which the powerful Thai defenders were able to deal with easily.
The match finished 0-0, with Vietnam bowing out of a competition they were favourites to win.
Thailand will face Indonesia in the final, while Vietnam will turn their focus to their final four World Cup qualifiers in early 2022.