Toàn was against three rivals from the Philippines, Timor Leste and Indonesia in the men's 89kg class.
In the snatch, he caught up with the current record of 150kg in his first attempt. He increased it to 155kg and succeeded to set a first new record. In his third attempt, he failed to lift 157kg.
In the clean and jerk, Toàn lifted 185kg and 190kg in the first two attempts. The 190kg was the new Games record. The 21-year-old tried 193kg in the last lift to set another record but couldn't manage the lift.
In total, his result of 345kg was his and Games' third new record.
Toàn won the gold, followed by Zul Ilmi of Indonesia (328kg) and John Dexter Febra Tabique of the Philippines (310kg).
In the last Games, Toàn finished third with a bronze.
It was the third gold of the weightlifting team this Games after Lại Gia Thành in the men's 55kg and Trần Minh Trí in the men's 67kg.
Also on the morning of May 16, Nguyễn Khoa Diệu Khánh and Nguyễn Đức Tuân won two bronze medals in table tennis.
Vietnamese athletes will take part in the finals of different sports later this evening.
Nguyễn Anh Tú will face Zong Isaac Quek of Singapore in the men's singles table tennis event.
Nguyễn Thị Hồng Trâm and Trần Huỳnh Như will compete in an all-Vietnamese final of the women's breaking of dancesport.
Wrestlers will take part in six finals of men's Greco-Roman. Judo martial artists will join in the team's combat events while kickboxers and arnis players will fight for their individual titles. Fencers will compete in the women's epee team and men's foil team.
On May 16, the Vietnamese Ambassador to Cambodia Nguyễn Huy Tăng and representatives of Vietnamese enterprises visited the Việt Nam sports delegation.
Speaking at the event, Ambassador Tăng expressed his pride and happiness witnessing the successful achievements of the delegation which temporally stay top of the medal table.
He congratulated all athletes and hoped that they would continue doing their best in the remaining events.
He expected that each member of the team would be an ambassador of peace, joining hands in strengthening the solidarity, development and friendship between countries in Southeast Asia.
In response, Chief-de-mission Đặng Hà Việt thanked Ambassador Tăng and said the delegation received strong support from the Embassy and the Vietnamese community in Cambodia during the Games.
Their support and encouragement played a key role in the delegation's success. They made up the family environment for athletes when they were competing far from home. Vietnamese athletes had earned outstanding results with 124 gold medals which exceeded their target of 120 set at home.
Currently, Việt Nam are in first place leaving nearest rival Thailand far behind with a gap of 31 golds while there is only 56 set of medals left on the last day. /.