Vietnam slipped a spot to the third position at the end of Day 8 of the South East Asian Games in Indonesia despite winning nine gold medals on Saturday.
While Vietnam has a total of 80 gold medals, Thai athletes won 17 contests Saturday for a total of 84 golds, climbing to second place behind hosts Indonesia who have 138 golds.
Vietnam's nine golds came in billiards, swimming and martial arts - wushu, judo and shorinji kempo.
Swimmer Chau Ba Anh Tu took gold in the men's 10km event after covering the distance in two hours 14 minutes 32.94 seconds. It was the second gold medal for the 21-year-old, who also won the men's 5km contest two days earlier.
Billiards player Nguyen Quoc Nguyen won gold in the 3-cushion carom event after beating compatriot Duong Anh Vu 40-36 in the final match.
Wushu martial artist Nguyen Mai Phuong put in a spectacular performance to grab gold in the women's long fist event, earning 9.71 points to inch past silver medalist Susyana Tjhan of Indonesia with 9.70 points.
In the judo contests, Bui Thi Hoa and To Hai Long won gold in the women's 63kg category and men's 81kg category respectively.
Chau Nguyen Quoc won gold medal in the men's 70kg category of the shorinji kempo event. Kempo is a Japanese martial art.
In the snorkeling event, swimmer Nguyen Thi Thuong won the gold in the women's 800m event while Duong Thi Huyen Trang took the gold in the women's 100m competition and Nguyen Trung Kien grabbed the gold in the men's 100m category.
With a total 80 gold, 75 silver and 77 bronze medals, the Vietnamese contingent is in third place behind top-placed Indonesia with 138 gold, 110 silver and 102 bronze medals. Thailand has regained the second place with 84 gold, 76 silver and 93 bronze medals.
Malaysia, Singapore, the Philippines and Laos are in fourth, fifth, sixth and seventh positions respectively, while Myanmar, Cambodia and Brunei are in the eighth, ninth and tenth places. Timor Leste takes the last spot.
In the gold medal tally, Malaysia has 47, Singapore, 39, the Philippines, 22, Laos has eight, Myanmar, 7, and Cambodia, 3. Brunei and Timor Leste are yet to win a gold medal. Brunei has two silver and seven bronze medals, and Timor Leste has three bronze medals.