Poland coach Jerzy Engel believes his side will not be the only ones to struggle against the South Koreans.
The Poles were swept aside by more dynamic opponents who scored a goal in each half to record their first ever World Cup finals win.
South Korea were backed up by fanatical support from the home fans in Busan's Asian Cup Stadium.
But Engel made no attempt to blame the partisan atmosphere for his team's failure to find the form they showed in qualifying.
Instead, he admitted that his men were simply second best on the night.
"A host team in the first game is always very difficult and they were better than us," he said.
"I can't complain," he added. "It's no accident that they drew with England and gave France a good game.
"They were very aggressive and are a very well organised team and I believe that here (in South Korea) they will be very difficult to beat.
"Portugal are the strongest team (in Group D) but Korea can hurt anyone."
Poland reached the finals with just one defeat in 10 matches.
But in Busan they looked pedestrian in defence and short on guile and variety in attack.
Engel confessed his disappointment in the lack of offensive threat posed by his men.
"My team only managed to create a few chances," he said.
"It was very disappointing for us - we had two chances in
the opening minutes and missed them.
"We wanted to win our opening match to challenge for first place in the group.
"Now we have to try to target second place and it will be very difficult."
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