South Korea coach Hong Myung-Bo blamed himself for his team's failure to progress past the group stage, following the 1-0 defeat to Belgium that eliminated them from contention.
Hong's men were the last of the four Asian teams to go out, after Australia, Iran and Japan, as AFC will not have a representative in the knockout stage.
South Korea, the second-lowest ranked side by FIFA entering the tournament, managed only an opening draw with Russia and finished bottom of Group H.
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"Regarding the other Asian teams, they all did their best," Hong said. "In our case, our players did their utmost and gave it their all. I think it was my shortcomings and failings as the coach that caused this result.
"There were a lot of trials and errors and our players did their best during the whole process. It is my failing that caused this result."
Hong said he would take time to decide if he would step down as coach.
"It's difficult for me to say right now, but it's something I will decide later on," he said.
On Thursday against Belgium, South Korea failed to break through, even after Steven Defour was dismissed just before halftime.
"When we played the full squad, we played quite well. We had the chance to counter-attack and when there was a red card, the situation changed and we became more aggressive," Hong said. "We concentrated too much in the center of the field after the red card.
"Our players always have a dream, but in order to realise this dream, we have to make a lot of efforts. Our players and myself have to work hard to reach this goal. We didn't have good results in this World Cup. Overall, there were a lot of deficiencies in Asian teams.
South Korea finished with a minus-3 goal difference, with the biggest blow a 4-2 defeat to Algeria in their second match.
"Our defense is very talented. If they play in other leagues, they will be able to gain experience. Up until now, they have worked hard, but I am not dissatisfied with my players," Hong said.
"The bad aspect was that in the match against Algeria, we conceded three goals in the first half and the team collapsed. That's one thing I regret to some degree, but our players were strategically prepared and I am quite satisfied.
"Personally, the main goal was for me not to have any regrets. We weren't up to the standard, but we did our best. It was important for our players to play at a big stage."