JOHANNESBURG (Reuters) - Secretive North Korea make a first return to the World Cup since 1966 on Tuesday but could hardly face a bigger challenge than five-times champions Brazil.

Hoping to recapture the form that famously took them to the quarter-finals in England back then, the ultra-defensive North Koreans have been training together for four months on a tour across three continents from Sri Lanka to Venezuela.

As with most aspects of their hermetic communist-run nation, mystery surrounds the tournament’s lowest-ranked team.

The North Koreans do, however, have a reputation for fitness, speed on the break and defense at all costs.

That could be a worry for Brazil, who have developed solidity but lost some flair under coach Dunga, and even at home failed to breach the defensive walls of lowly Venezuela, Colombia and Brazil in World Cup qualifiers.

“Nobody talks about them but they play good football,” said Ivory Coast manager Sven-Goran Eriksson of North Korea.

Ivory Coast are in the same Group G and hope captain and inspirational striker Didier Drogba will declare himself fit to take on Portugal and their wing wizard Cristiano Ronaldo in another match on Tuesday.

Drogba has a fractured forearm.

North Korea are not the only underdogs hoping for a shock.

New Zealand and Slovakia face off in the opening game, both dreaming of becoming the World Cup’s surprise package.

Better known as a rugby nation, New Zealand’s All Whites are hoping to do better than their only previous appearance at a World Cup when they lost all their group games in 1982.

“It’s been a long time, hasn’t it?” said coach and former All Whites defender Ricki Herbert, remembering how he swapped shirts with Brazil’s Socrates after a 4-0 drubbing.

Playing their first World Cup as an independent nation, Slovakia’s coach Vladimir Weiss also has past experience in the tournament. He was part of the Czechoslovakia team that reached the quarter-finals in Italy in 1990.

JABULANI, VUVUZELA DEBATES RAGE

Only Germany have really sparkled so far in the early games of the first World Cup on African soil, their young side’s 4-0 hammering of Australia sending a shudder through rivals.

Netherlands have a talent-packed team, but with winger Arjen Robben missing through injury, they failed to shine in a prosaic 2-0 win over Denmark at Soccer City on Monday.

Other European heavyweights, Italy, followed their tradition of slow starts with a 1-1 draw against Paraguay on Monday, the aging “Azzurri” team coming from a goal down to avoid an upset.

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African nations have registered only one win so far, Ghana beating Serbia on Sunday to spark parties across the continent.

Another of Africa’s best hopes, Cameroon, were surprisingly humbled on Monday by Japan, who beat them 1-0 in their first World Cup finals victory on foreign soil despite a dire string of results in pre-tournament warmups.

“To be honest the mood was not the best but ... our team delivered our best,” goalscorer Keisuke Honda said.

Off the pitch, hosts South Africa are delighted at the smooth running of a tournament doommongers said they would be unable to handle.

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The only serious problem in the first four days came when police teargassed stewards protesting over wages in the coastal city of Durban after the Germany-Australia game on Sunday.

Controversy is growing among players and coaches alike over the World Cup’s new ball, called the Jabulani after the Zulu word for celebrate. Crosses, free-kicks and long-range shots have been skying over their targets, and players are nervous.

“The ball is tricky and not just for the keepers but for all the players,” Danish goalkeeper Thomas Sorensen said after his team’s defeat to Netherlands, adding attitude was a factor too.

Debate will not go away either over the ubiquitous local vuvuzela trumpet, which creates a deafening wall of sound like a gigantic swarm of bees inside stadiums.

Supporters say it is an essential part of local culture, while critics hate the vuvuzela for drowning out crowd chants, preventing communication between players and coaches, and creating a din that has many reaching for earplugs.

Talk of outlawing them has been squashed though.

“Vuvuzelas are here to stay and will never be banned,” said Rich Mkhondo, a spokesman for the local World Cup organizing committee. “As our guests please embrace our culture, please embrace the way we celebrate.”

Meanwhile, sales of vuvuzelas -- and earplugs -- continue to go through the roof, according to their manufacturers.