The 71-year-old German said his side's opponents are fast, determined and tactically astute and told his players that the Koreans will pounce if their concentration lapses in their Group B encounter at a wind-swept and chilly Port Elizabeth.
"In 1962 I travelled through Asia and played local teams and won 6-0, 7-0 and even more," said Rehhagel. "That was long ago and since then the Asian teams have caught up massively. They have wonderful ways to move and we really can't imitate that as Europeans. They run like panthers – they're like big cats. They're very clever when it comes to tactics, they know what football's all about.
"I've told my guys that if you think for a fraction of a second that you can afford not to pay attention, you'll be badly sanctioned," he added.
The Greek players, including Celtic's Georgios Samaras, are keen to forget their miserable World Cup past having lost all their games and failed to score a single goal in their sole appearance in 1994.
Captain Giorgos Karagounis, a veteran of their shock Euro 2004 triumph, said ambition had got the team through to the finals and they would show it again against a slick and speedy South Korean side.
He played down talk that Greece, who typically play with one striker – most likely Samaras – are not attack-minded, but admitted clean sheets are the team's priority over goals.
"We go forward and we try to score, we wouldn't have achieved much without scoring," he said. "Of course, our main feature is our compact defence and our main target is not to concede. We will start by trying to not concede a goal."
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