Sonny Bill Williams, Richard Kahui and Israel Dagg won special praise but the All Blacks overall performance failed to inspire the country when they beat Tonga 41-10 in the World Cup opener.

The makeshift backline combination, also including Isaia Toeava, were instrumental in ensuring the All Blacks successfully produced their trade-mark running game in the first half as the raced to a 29-0 lead.

But the fairytale performance the All Blacks hoped for to match the spectacular opening ceremony on Friday before a packed crowd of 60,000 did not materialise.

After four snappy tries in 30 minutes it was half an hour before they were able to cross the line again as minnows Tonga overcame initial stagefright to show they could operate at senior level.

All Blacks skipper Richie McCaw, now in his third World Cup, gave credit to the islanders who "played their part in defending pretty well" but it did not explain why the All Blacks allowed them back into the game.

A more direct answer came from two-try wing Kahui who said the improvement by Tonga after the break was only part of the reason for the All Blacks decline.

"The other half is because we didn't really switch on, we almost put it into cruise control and you can't do that certainly if you want to be a quality side," he said.

"You've got to put teams away when you've got the chance whether it's Tonga or Australia or whoever."

The New Zealand Herald noted the "embarrassment" of Tonga scoring a try while the All Blacks "messed up a multitude of try-scoring chances" after half-time.

"It was a strange watching the All Blacks fail to reignite their game. They rushed some moves, botched others and looked sloppy compared with their initial cohesion."

Fairfax media rated it a mixed performance providing "a spectacle of running rugby" and "a sloppy second half where several opportunities went begging."

"Whether this New Zealand approach survives sterner tests remains to be seen in this seventh edition of the global event."

It is unlikely other tournament heavyweights Australia, South Africa, France and England would have been shaken by the All Blacks show and kickers like Jonny Wilkinson would smile at the 13 penalties conceded by the men in black.

All Blacks coach Graham Henry knows that, and began dissecting the game as soon as referee George Clancy blew the final whistle.

"We scored some good tries, got maximum points, defended well, had a good structure, made too many mistakes and gave away too many penalties so a bit of work to be done," he said.

Henry rated the performance "six or so" out of 10, but could not hide his pleasure at the performances of Williams, Kahui and Dagg.

Williams "played particularly well particularly on defence, made a lot of good tackles. He's also a threat and creates a lot of opportunities for those around him" he said in reference to three tries resulting from the former rugby league star's uncanny offloads.

Henry said more would be seen of specialist centre Kahui on the wing after his two-try outing and rated Dagg as a threat who was the last passer in a couple of tries.

The All Blacks next game is against Japan in Hamilton on September 16.

AFP