Erasmus backs New Zealand for World Cup

South Africa coach Rassie Erasmus said New Zealand remain the favourites for the Rugby World Cup, but warned they will face tougher challenges than his Springbok side later in the competition.

New Zealand claimed a 23-13 opening Pool B victory over the Boks in Yokohama on Saturday in a game in which they had less of the ball, but capitalised on South African errors to score two tries to one.

Erasmus said he believed the defending world champions were full value for their win and admitted his team were perhaps not the litmus test for the All Blacks' potential to lift the trophy in Japan.

"People must remember we are (ranked) four or five in the world and there are teams that will handle their kicking game and the specific things they do a little better than we did," Erasmus told reporters.

"We have played them six times in the last few three years so we know each other well, but I think they are definitely the favourites for the World Cup and they have always been. We have never had a doubt about that.

"We just feel we are creeping a little bit closer and challenging them. But they will have different challenges against teams like England, Ireland and Wales, who bring different threats to the party."

Erasmus admitted New Zealand were able to neutralise his team's key attacking weapons, stifling their opportunities for points.

"We bring physicality, but they handled our maul, scrum and kicking game pretty well. But when you play teams like Wales and England, they have totally different strengths.

"So by all means I think New Zealand are the favourites, without a doubt, but they will have different tactical challenges against the Northern Hemisphere teams and it will be interesting to see how they handle that.

"But I also think I must stop commenting on them, we have got a hell of a lot to sort out ourselves."

South Africa are still expected to advance to the quarterfinals, with the key game for them in their pool now an October 4 meeting with Italy in Fukuroi City.

They are next in action against Namibia on Saturday and meet Canada in the final game in their pool on October 9.