It has been Stephen Kearney's main concern over the last few years, and on the evidence of the past week, continues to be the Kiwis' Achilles heel.
If the Kiwis are to retain the World Cup, maintaining an intensity of performance across the full 80 minutes is the crucial ingredient.
This team is definitely good enough to compete with - and beat - both England and Australia - but it will take a concentrated, focused effort of the kind that has been rare in the past few years.
"We have learned that we can't afford to switch off at any time," Kearney told the Herald on Sunday back in July. "The Australians always punish you, they always take advantage of any lapse."
The game against Samoa last Monday was disturbing not so much for the way the Kiwis eased off the throttle in the second half (it can happen) but more for their inability to wrest back control of the match, as they allowed the Pacific side to score four tries in 12 minutes. This wasn't the Kiwis' typical slow start to the tournament; in fact they began well before their second half fade.
Yesterday's match against France was better, a more concerted effort but still phases where concentration seemed to dip, especially before and after halftime.
Untimely lapses in games have plagued the Kiwis down the years and continued throughout the Kearney era. It can partly be explained by the relentless pressure that the Australians in particular exert - the levee will usually break at some stage - but it's been too common.
The most recent example was this year's Anzac test. After shading the first half and with the scores tied at 6-6, the Kiwis unravelled in a 15-minute period after halftime as the score blew out to an irretrievable margin. It was a similar story in Townsville last year; 10-10 after the first half and a gutsy, brave performance but ultimately an 18-10 loss after Australia lifted the intensity in the second half.
While the focus is on the Kangaroos, who are almost guaranteed to reach the final following their victory over England last week, the home side will be a formidable barrier in the Kiwis quest. This looks the strongest English team since the glory days of the late 1980s and early 1990s, with their forward pack particularly potent. The Kiwis have traditionally struggled on English soil and haven't beaten England in the Northern Hemisphere since 2006.
