Leading 1-0 at the break through Raul Meireles strike, the Europeans added six more in the second half through Simao, Hugo Almeida, Liedson, Cristiano Ronaldo and two from Tiago.
Portugal started brightly and, predictably, it was Ronaldo who had the first shot on target, testing goalkeeper Ri Myong Guk with a low drive.
Ricardo Carvalho then had two great chances in the space of four minutes – first firing over on the turn from about eight yards out, then thundering a header from a corner into the upright.
However, slowly but surely the Koreans started finding their feet, with Cha Jong Hyok firing in a powerful effort from 20 yards which had Eduardo scrambling, before Hong Yong Jo stung the keeper’s palms, but the follow-up into an empty net went over.
Kim Jong Hun’s men kept testing the Portuguese keeper from distance during an excellent spell, but it was the Europeans who opened the scoring on 29 minutes – Meireles running onto Tiago’s perfect through-ball before finishing well.
Meireles had another brilliant chance just before the break when the Koreans failed to clear in the area, but he dragged his close-range effort wide.
If the Koreans were harbouring any hopes of coming back into the game, they were shot down in an incredible seven-minute spell for Portugal.
Tiago sounding the warning signs when his long-range shot needed to be tipped over, but there was no mistake on 53 minutes when Almeida and Meireles combined on the edge of the area before playing in Simao, who put the ball through the keeper’s legs.
Three minutes later and it was 3-0 – this time Tiago played Fabio Coentrao in down the left, and his perfect cross was expertly finished by Almeida.
If the Koreans thought it couldn’t get much worse, they were wrong – Ronaldo went flying down the left and cut the ball back for Tiago, whose shot was too strong for the keeper to keep out.
Meireles should have made it five later on, and Ronaldo almost did as his 20-metre rocket skimmed the top of the crossbar.
A fifth did come though – Liedson, with his first touch after coming on, fired past Ri Myong Guk after a defensive slip-up.
And just before the end Ronaldo did get his name on the scoresheet, running onto a backpass and lifting it over the keeper, before Tiago rubbed salt in the wounds, heading home from 10 yards out for his second
The result puts Portugal right back in the reckoning, and they and Brazil will now fight it out for top spot in the group.