By all accounts the second half that New Zealand produced against Namibia was pretty special. It wasn’t the fact that they scored seven tries in 40 minutes, or that they nilled their opponents who had given the first half a mighty good crack, but it was the type of rugby they produced that demonstrated why they sit on a level just above the rest.

It is why the All Blacks are gunning for a third consecutive Rugby World Cup, but there is a problem.

The first half of the 71-9 Pool B victory was not impressive in the slightest. New Zealand may have secured the bonus point before half-time, but at 34 minutes in they led by a solitary point, 10-9 after two unconverted tries from Sevu Reece and Anton Lienert-Brown.

Steve Hansen knew this, and sent a rocket up the backside of his players to start doing what they do best in the second half: play rugby.

"The first half was not the right attitude and we allowed Namibia to partake a lot more than they should have, and that’s not being disrespectful,” Hansen said after the match. “We came out in the second half with a lot more understanding of what we wanted to do.

“With opposition you know you should beat, players, coaches and management can get a little lost in the mental preparation, for want of a better word.

"It is not a major issue but a reminder that you have to be mentally right to perform at the level you want to perform."

It says a lot that Hansen identified this, even though at 24-9 up at half-time New Zealand never looked like they were going to lose the match at the Tokyo Stadium. The fact that coaches of both teams found it difficult to answer the question of whether a team like Namibia will ever be able to beat the All Blacks says everything you need to know about the gulf between these two rugby-playing nations, but that did not stop the African side threatening an upset until Hansen tore into his players.

"It was one of the better ones I've heard,” said hooker Dane Coles of Hansen’s team talk at half-time. “And rightly so, to be fair. We deserved it. It was a nine or 10 out of 10. It was good, a bit old-fashioned, you don't really see that too much these days. But I think it was just what we needed to get things going.

"When that first word came out of his mouth I knew something was on."

Hansen wasn’t too impressed with Coles revealing his hairdryer treatment approach, given it shows that the former policeman fully understands the danger facing his side. Since beating the Springboks in emphatic fashion, New Zealand have thrashed Canada 63-0, and Namibia 71-9. They have not conceded a try, not had to defend their line and not faced anything close to what they awaits them in the semi-finals, and even though their final game in Pool B is against an Italian side who can still qualify for the last eight, South Africa’s final fixture against Canada should see Rassie Erasmus’s side safely through.

It means that New Zealand risk being drastically undercooked when they reach the quarter-finals. Exactly the same happened in 2007, when the four pool matches against Italy, Portugal, Scotland and Romania provided a combined score of 309-35 in the All Blacks’ favour. Upon reaching the quarter-finals, the were dumped out by France in their famous Cardiff encounter.

That’s why TJ Perenara, the experienced 62-cap scrum-half, knows that Sundays first-half scare against Namibia needs resolving now, with the belief that if they can correct those mentality issues within the squad, they don’t have to worry what they face in Ireland, Scotland or Japan – their three potential opponents in the last eight.

“I’m a big believer in regardless of opposition, regardless of circumstance and the context of a game, we should be competing against ourselves, both as a group and individually,” Perenara said.

“Try to be the best me that I can be and be the best team that we can be, so regardless of the game we’re playing in, if we can continue to try and strive to be better day to day, better week to week, then context becomes irrelevant because we’re competing against ourselves.

“That’s my personal opinion how you do it, you take the external pressures of the game out regardless of who you’re playing. You take it away and just compete against yourself day to day.”

New Zealand will not know is that is the right solution until the Saturday night on 19 October, when their quarter-final reaches its climax and Hansen’s squad know if they’re on for a three-peat or not.