The young Golden Stars were Group C’s leaders while the junior War Elephants followed in second due to goal difference before the match.
Thailand pressed in the first half, but Vietnam were deadly on the counterattack front.
One of those moments was Nguyen Trung Thanh’s converting of a free kick with a shot that Thai goalkeeper Narongsak Nueangwongsa was able to get a hand on but could not punch away to help his team take the lead in the 29th minute.
The Thai players piled on the pressure in the remainder of the first half but failed to find an equalizer.
Both teams seemed to try to keep their core players fit for the semifinals only two days away as the second half was not too eventful.
Thailand’s best chance of the night was denied by Vietnamese goalie Trinh Xuan Hoang’s fingertip in the 83rd minute.
It was Xuan Hoang again who saved Quang Thinh from an own goal three minutes later.
The hard-fought victory earned Vietnam three more points to ensure their top spot in Group C while Thailand remained in the second place.
|Vietnamese (red jersey) and Thai players vie for the ball during their group-stage game at the ASEAN Football Federation (AFF) U23 Youth Championship in Cambodia, February 22, 2022. Photo: Hoang Tung / Tuoi Tre
The result set Vietnam in a semifinal on Thursday against Timor-Leste, who had topped Group A.
Meanwhile, Group B winners Laos will compete against Thailand in the other semi on the same day.
The 2022 AFF U23 Championship, which has experienced the personnel woes caused by COVID-19, has three groups.
Group A has hosts Cambodia, Timor Leste, the Philippines, and Brunei while Group B includes Indonesia, Malaysia, Myanmar, and Laos.
Indonesia and Myanmar have backed out of Group B because of a myriad of COVID-19 infections on their teams.
Vietnam and Thailand were drawn in Group C alongside Singapore, who kicked off their campaign at the tourney with a 1-3 loss against Thailand on February 16.
The top team of each group and the best runners-up qualify for the semifinals.
The championship started on Monday and will conclude on February 26.