Speaking after the match in Uzbekistan, he said: "Vietnam did not win and I'm sorry about that. We had to share points in the last two games. Vietnam still have one more game to go. I really appreciated the effort of the players. They tried their best in this game."
Vietnam drew 2-2 against Thailand in their first game at the tournament last Thursday.
South Korea dominated the Sunday match with 74 percent possession and 11 shots, including two on goal. The excellence of Vietnam's defense, especially the center-back duo Bui Hoang Viet Anh and Nguyen Thanh Binh, and goalkeeper Quan Van Chuan helped the team keep the threat at bay.
Even after South Korea scored first in the 63rd minute Vietnam did not panic and responded with a few attacks of their own.
In the 78th minute South Korea were down to 10 men after Lee Jin-yong received a second yellow card. Taking advantage of this, Vietnam increased the pressure and equalized with a stunner by Vu Tien Long. It was Vietnam's only shot on goal in the game.
"I didn’t have a plan to draw against South Korea," Gong said.
"I always encourage the players to aim for victory. I told the players to fight and win. South Korea were really strong but Vietnamese players ran more and put in more effort.
"They have showed confidence since during training. Before the game, I told them to create a surprise and they did it."
Before Sunday Vietnam had only drawn once and lost four against South Korea at the U23 level.
On Wednesday Vietnam take on Malaysia in the last fixture of group C, while South Korea play Thailand.