The team were heavily trained on pressing, constant movement, teamwork and finishing from narrow angles.
Gong will use the 4-3-3 formation, which is different from previous coach Park Hang-seo, who used 5-3-2. The new formation requires mobility and flexibility.
"This formation focused on attacking, using short passes to deploy, while coach Park highlighted the defense and preferred counter-attacking," defender Tran Van Cong told VnExpress.
Gong gave the captain armband to defender Bui Hoang Viet Anh, while the two vice-captains are goalkeeper Nguyen Van Toan and midfielder Ly Cong Hoang Anh. Those three are key players in the Vietnam squad that won SEA Games 31 gold last week.
"Those players are experienced and we can learn from them," forward Vu Minh Hieu said.
The U23 team are set to play an exhibition match with the UAE on Saturday. A day later, they will fly to Uzbekistan for the U23 Asian Cup, which takes place from June 1 to 19. This will be Gong's first tournament as head coach of U23 Vietnam.
In the group stage, Vietnam will face Thailand on June 2, South Korea on June 5, and Malaysia three days later.