Champions New Zealand underwent a punishing first World Cup training session in Japan on Wednesday before promising to come out firing against South Africa in their blockbuster tournament opener.

The treble-chasing All Blacks, who face the Springboks in a potentially explosive Pool B clash on September 21, began their workout at 8:00 am local time in Kashiwa, northeast of Tokyo, to avoid the brutal afternoon heat.

“I'll give you a quick summary - it's very hot,” said New Zealand assistant coach Ian Foster, noting that temperatures hit 38 Celsius (100 Fahrenheit) on Tuesday.

“We changed the timing of our training just to adapt to the heat in the afternoon. It's common sense - but we're loving it.

“We had a number of players who we held back last week with niggles. We're pleased with the progress we've seen and that's put us in a good spot,” he added, confirming that fly-half Richie Mo'unga should recover from his sore shoulder in time to face South Africa.

“It's the first time in three years we've had a week of training without a game at the end. That's probably why we got a bit of a bounce today with a really solid session. The guys are feeling really good about what we're doing.” The All Blacks, who smashed Tonga 92-7 last weekend in a World Cup warm-up in Hamilton, also meet Italy, Canada and Namibia in Pool B.

But their showdown with the Springboks, who held the All Blacks 16-16 in Wellington six weeks ago and beat them to the Rugby Championship title, is set to be a classic and could set the tone for the World Cup.

'Confident' Springboks

“We love the draw because it's meant we've turned up and there's no excuses, no waiting for us to get used to the intensity - it's right there in front of us,” insisted Foster.

“We're about to face a very confident South African team, but they're going to face a very determined All Blacks team - we know South Africa are going to be 100 percent prepared and we've got to make sure we are too.” The Springboks limbered up for the World Cup by beating hosts Japan 41-7 in Kumagaya last Friday to partially atone for their humiliating loss to the Brave Blossoms at the 2015 tournament.

But Foster paid tribute to Japan, who kick off the World Cup against Russia in Tokyo on September 20.

“I think we saw a very brave Japan team play with a lot of possession,” he said. “They really challenged South Africa defensively for large periods of the game.” Foster meanwhile shrugged off suggestions that New Zealand were showing glimpses of fallibility, after drawing with the Boks and losing to Australia in the Rugby Championship.

“Winning has always been important to us, but it really doesn't mean much now,” he said, adding: “There's a number of candidates putting their hands up to be favourites for this tournament.

“We've seen a number of teams who've had big victories that we've looked at and gone 'Wow, that's a team that could really threaten!' So it's going to be an exciting World Cup - but the rest is just a smokescreen really. “

- AFP