The Group H hopefuls were beaten 4-0 by Ghana on Monday in their final warm-up friendly before taking taking on Russia next week.
Even Ghana coach Kwesi Appiah was critical of Hong's side - advising them to be more "careful in defence".
Offering his views, the former South Korea international highlighted individal slip-ups rather than a wider-ranging problem.
"I don't think it was systematical errors but rather mistakes of a few individual players that led us to give up the first two goals, which later led us to a rout," Hong explained.
"I think players were under huge pressure as it was our last test. They were all tense and could not give a 100 per cent performance."
The coach went on to claim his side can fix their defensive frailties.
"Only about a week is left before we have our first game against Russia but we can fix the problems in a short period of time and that's football," he continued.
"Although we were defeated, I hope it will have a positive impact on the players."
South Korea will also face Algeria and Belgium in their World Cup group.
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