"We thought that when the opponents had a lot of energy it would be better to use Son later in the game, when they started losing energy and there was more space. We wanted to use him when they were weaker," Hong said.
Son replaced Hwang Hee-chan at half-time but had little impact in the 1-0 loss.
"We prepared well, but compared to our previous matches we made too many mistakes in midfield. That's why my players lost confidence. We knew how we should have played, but we should have done better. Today's performance was simply not good enough," Hong added.

South Korea finish third in Group A with three points from three games.
Qualification depends on results from other groups.
