Brazil legend Zico believes North Korea will need to be at their best if they are to create a shock and progress from a tough group at the World Cup.

The East Asians open their Group G campaign against five-time World Cup winners Brazil on June 15 before playing Portugal and the Ivory Coast.

Zico said: "Brazil are a very strong team and so are Portugal, so North Korea need to be at their absolute best to be able to get through the group."