Striker Son Heung-min blamed himself for South Korea's 1-0 defeat by Sweden in their World Cup opener, saying he did not do enough to help lift his team mates in their Group F game.
Son is regarded as the only world-class player in the Korean side and he felt a burden of responsibility given his profile from the Premier League.
"I'm really disappointed with my own performance. I feel I should be the one who makes things happen for my team mates but I didn't play well," Son told reporters.
"It didn't go to plan and I just didn't play well," the Tottenham Hotspur forward added.
"Son started on the right side of a three-man attack, but was largely anonymous as his team did not manage a single effort on target.
"We forwards have to responsibility for this. When we won the ball, we still had too much distance left to go forward," he said, looking crushed and sighing often as he answered questions in both Korean and English.
Overall, it was a disappointing performance that left the Koreans, with games to come against Mexico and Germany, on the back foot.
"It's pity that we didn't get a good result. We knew it was important to not surrender a goal first," Son added.
"If we conceded one, wed have to score two, so we played very cautiously.
"We had all worked hard to prepare for this match. We have to accept this result and reorganise ourselves for Mexico."
"But they played really well to beat Germany. They were quick. But (upsets) like that sometime happen in football. If we can be mentally strong we could do the same but the World Cup is no easy stage," Son added.
South Korea play Mexico in Rostov-on-Don on Saturday before meeting world champions Germany.