All Blacks coach Steve Hansen has reminded two of his most accomplished players that nobody is above the law following their scratchy 26-16 win over Argentina at the Rugby World Cup.

The world champion New Zealanders opened their title defence with a come-from-behind win against defiant opponents at London’s Wembley Stadium.

Swarming Pumas defence frustrated New Zealand until the last 25 minutes when the world champions were able to score both of their tries through halfback Aaron Smith and reserve flanker Sam Cane.

For long periods, the All Blacks were unable to generate any flow despite dominating possession against opponents who led 13-12 thanks to the sole try in the first half scored by lock Guido Petti.

New Zealand’s first half was marked by four penalties to first five-eighth Daniel Carter and yellow cards shown by referee Wayne Barnes to two other veterans – captain Richie McCaw for tripping and centre Conrad Smith for a professional foul.

Hansen says both cards were warranted and the pair should have known better, leaving New Zealand with 13 players on the field at one stage late in the first spell.

“The two yellow cards today were pretty dumb. Rich and Conrad know they were dumb ones and sometimes in the heat of the moment you have a wee brain explosion,” Hansen said.

McCaw said he knew straight away he was in trouble after tripping opposite number Juan Martin Fernandez Lobbe, earning the third yellow card of his career.

“It was one of those things that as soon as that happens you wish you hadn’t.

“It was a reflex thing. I suffered because of it and put the team under pressure which wasn’t the right thing to do.”

McCaw’s mistake was symptomatic of the frustration New Zealand felt at being unable to create fast ball and space in their first game for six weeks.

Those issues continued as they trailed 16-12 through 55 minutes before Argentina’s intensity began to wane.

The most experienced team in Test history – boasting 1013 caps in their starting team – had the means to capitalise as the game opened up in front of a tournament record crowd of 89,019.

Smith darted over from some loose ruck ball before Cane was on the end of an overlap, taking the last pass from replacement second five-eighth Sonny Bill Williams, who was energetic for the last half-hour.

Hansen says the impact of his reserve bench was vital.

“There’s no doubt we were rusty, really rusty. Not only were we rusty, there’s a lot of apprehension in most of the teams,” he said.

“Everyone’s been half-a-second off the pace. That’s what comes with the World Cup, especially first round.”

Argentina counterpart Daniel Hourcade lamented his eighth-ranked side’s inability to stay the distance.

“It got to a point where they (NZ) reacted, they took the ball and they never gave it up,” Hourcade said.

Carter landed all six shots at goal in a 16-point haul while opposite Nicolas Sanchez was also perfect with four shots and 11 points.

New Zealand remain unbeaten in 22 Tests against Argentina but this was their narrowest win in eight Tests since 2006.

The tournament favourites go straight to the top of pool C, ahead of Georgia on points differential.

They have a four-day turnaround before facing Namibia at London’s Olympic Stadium and complete a relatively light pool schedule against Georgia and Tonga.