Park's first match as coach of Vietnam was in the same 2019 Asian Cup qualification, where Vietnam held Afghanistan at home in a 0–0 draw, thus allowed Vietnam to qualify for the 2019 AFC Asian Cup, their first ever Asian Cup since 2007. Park himself, though, was criticized. However, the mood changed after Vietnam's performance in the 2018 AFC U-23 Championship and 2018 Asian Games. Park Hang-seo was also coach of the U-23 and Olympic team. With the same U-23 players, he formed the squad of Vietnamese senior in a meaningless 1–1 draw to Jordan in 2019 Asian Cup qualification, which both teams qualified together. Also with these young players, the 2018 AFF Championship became Vietnam's second AFF Championship title. In Group A, Vietnam managed 3 victories against Laos, Malaysia, Cambodia and a draw with Myanmar. In the semi-finals, they defeated the Philippines twice, and in the finals defeated Malaysia 3–2 aggregated, drawing 2–2 away and winning 1–0 home.