The All Blacks concede their slow start against Uruguay is a cause for concern, but they're bullish about their chances of winning their World Cup quarter-final.
The three-times champions were kept to 0-0 by Uruguay for the first 20 odd minutes in their final pool game, with the South Americans almost scoring several times as New Zealand made multiple errors.
All Blacks coach Foster concedes they won't get away with a start like that in the playoffs.
"We didn't like that start.
"I thought it was a mental looseness and we started to look for some passes and stuff that weren't on.
"I don't necessarily feel it was a skill issue or us not responding well to pressure. I think it was a mindset issue where you feel like you can go into a game and play before you've earned the right to."
New Zealand's opponents in their first knockout match will be revealed this morning, after Ireland play Scotland in Paris.
All Blacks midfielder Jordie Barrett is aware they could next face either of those sides - or South Africa - but insists he'll take any outcome in his stride.
Barrett believes the All Blacks a better team than the one that lost to France in the tournament opener a month ago.
"We're driven to get better every single week and I felt we've done that this World Cup.
"We had a bit of a blip at the start of the tournament but that was a quality French side and I feel we've gained a wee bit of momentum each week. Only time will tell."
Foster insists knockout games at the World Cup don't have to be low scoring and and dominated by kicking and he said his side won't move away from their desire to produce expansive rugby just because of the way other teams play.
"Not all playoff rugby is like that. Some teams want to make it like that and if they're good enough to put you into that position then you have to adapt. But we don't want to shut down our DNA and way of doing things just because people say that's the way it's going to be."
Foster concedes it will be difficult to win three knockout matches in a row in France, which they'll need to do to win the title.
He insists they won't look any further than the quarter-finals, but he knows the former champions have a tough task to lift the William Web Ellis Cup in Paris.
"The fact is that only one All Blacks team has done this away from home in the last seven away World Cups. That tells you how hard it is.
"We've got to keep reminding ourselves about that so there's no area of complacency in this group whatsoever.
"We know the size of the challenge."
The All Blacks are still yet to decide on whether to replace prop Tyrel Lomax in the squad after he picked up a knee injury, thought to be a medial ligament strain, in the win over Uruguay.
Foster said they won't replace him in the squad if he's only unavailable for the quarter-finals.
Lomax would be unable to rejoin the team if he is replaced and Foster said they have a couple of days to make a call.
"Clearly if you jump in early you can't get that player back. If it's not a significant injury and it keeps Tyrel out for a game we might be a little bit loathe to make that replacement."
-RNZ