"We know there’s a lot of pressure on and we’re feeling that. But our job is to look at our performance and how we can grow it," he told New Zealand media.
"I understand the frustration, but that doesn’t change what we have to do here.
"There’s no point sulking about it for too long. We’ve just got to get into Ellis Park and keep growing our game and still believe."
Many in New Zealand no longer believe in the team under Foster.
In a front page editorial on Monday, the New Zealand Herald, the country's largest newspaper, said Foster needs to go, calling him a "decent man who is out of his depth in a brutal business".
'No point sulking': Foster faces up to All Blacks criticism
Embattled All Blacks coach Ian Foster has urged his players to move on quickly from their Mbombela mauling and focus on the rematch with the Springboks at Ellis Park this weekend.
The All Blacks' 26-10 defeat in the Rugby Championship opener was their worst in 94 years in SA, triggering fresh calls in New Zealand for Foster to be sacked.
The three-time world champions have now slumped to a record low fifth in the world rankings and head to Johannesburg after a fifth defeat in six Tests.
With another loss to the Springboks on Saturday widely expected to make Foster's position untenable, the coach said players and staff need to take a deep breath.
"We know there’s a lot of pressure on and we’re feeling that. But our job is to look at our performance and how we can grow it," he told New Zealand media.
"I understand the frustration, but that doesn’t change what we have to do here.
"There’s no point sulking about it for too long. We’ve just got to get into Ellis Park and keep growing our game and still believe."
Many in New Zealand no longer believe in the team under Foster.
In a front page editorial on Monday, the New Zealand Herald, the country's largest newspaper, said Foster needs to go, calling him a "decent man who is out of his depth in a brutal business".
Foster's hopes of rallying his team at Ellis Park appear bleak, with injury concerns over flyhalf Beauden Barrett and his fullback brother Jordie.
Beauden has a sore neck after landing heavily from a mid-air tackle by SA winger Kurt-Lee Arendse, who was red-carded for the rash challenge, while Jordie left the field with an ankle injury.
Foster complained that Arendse had also clattered into Jordie unfairly as the All Black rose for a box kick in the 11th minute. Barrett was instead penalised for a knock-on.
Foster confirmed the All Blacks would be addressing SA's mid-air challenges with officials and said he expected more protection.
"It’s becoming a free-for-all for jumpers just to be able to jump and stick a hand out and say they’re competing. It needs to be addressed," he said.