Brad Friedel put the USA on the brink of qualification for the second phase of the World Cup and left the Korean nation in disarray.
Keeper Friedel saved a first-half penalty from Lee Eul Yong and made a string of wonderful saves to keep his country in with a change of progress from Group D.
The penalty was harshly awarded by Swiss referee Urs Meier for a foul by Jeff Agoos on Hwang Sun Hong when it was the Korean striker who had a handful of the American's shirt.
Friedel said: "I didn't think it was a penalty, their player was pulling Jeff, but I don't want to have a go at the referee because I felt he did okay."
He added: "We are delighted with the point. If anyone had said before the tournament that the USA would have four points after the first two games and be on the brink of qualifying, nobody would have believed them.
"But I think you have to give Korea some credit. They put us under a lot of pressure in the second half and it was difficult to withstand it all."
The Americans came under intense early pressure with Friedel outstanding, but they weathered the storm and broke away for Clint Mathis to drive home after 24 minutes.
Korea powered back and looked like they had been given a lifeline with that penalty.
But Friedel plunged to his right to beat out Lee Eul Yong's effort.
The second half was very much the Americans' back line of defiance against Korea's surging attacks and a string of chances - all stopped by Friedel until the 77th minute, when substitute Ahn Jung Hwan, the Perugia striker, headed home a free-kick.
But the USA and Friedel hung on grimly to their precious point and now go into their final group match against Poland with a very real chance of qualifying - as have Korea who must overcome an ageing Portugal.
Korean coach Guus Hiddink bemoaning missed chances.
He said: "We had a lot of good openings, maybe as many as nine, and you must take them at this level."
The Koreans marched in stony silence past the massed ranks of their country's media without a single word of explanation.
They had stood up to a physical battering and carved out enough chances to have won.
Hiddink said: "I am happy about the way we performed and our attitude when we went behind."
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