The two sides were only separated by Raul Meireles' goal at half-time, but Portugal produced a scintillating attacking display after the break to score six goals and spark their tournament into life, while ending North Korea's hopes of progressing.
Simao, Hugo Almeida and Tiago found the net in the space of seven minutes to end any hopes of a North Korean comeback, before Liedson, Ronaldo and a second from Tiago completed a similar quick-fire salvo at the end of the game.
Portugal face Brazil in their final match, and even if they were to lose and Ivory Coast win it is likely Portugal would go through, owing to a much better goal difference.
Scoring Action :RAUL MEIRELES (29')
HUGO ALMEIDA (56')
TIAGO (60', 89')
CRISTIANO RONALDO (87')