'Express yourself', Foster tells All Blacks
While stung by a 21-24 loss to the Lions in Wellington, Foster said "it's not all doom and gloom for us" as the third Test looms in Auckland on Saturday.
"We've done some really good stuff in the last two weeks, but it's pretty clear that there's more in us," he said.
"We've got to focus on that and make sure that in all circumstances – whether it's wet and cold or windy or whatever – we're still able to express ourselves when we want to.
"We've proven we can get parity [in the forwards] and front-foot ball and we've got to make sure we're smart in using that."
The reigning world champions were convincing 30-15 winners in the first Test at Eden Park, where they out-muscled the Lions forwards.
The Lions then hit back a week later after Sonny Bill Williams' sending off for a shoulder charge reduced the hosts to 14 men for much of the match.
Neither encounter featured the All Blacks' trademark expansive game, with Lions coach Warren Gatland saying he was yet to see them play "champagne rugby".
Foster said the Wellington defeat hinged on the red card, a situation the All Blacks had not faced for 50 years and was difficult to plan for.
He conceded the All Blacks, while still controlling the game for long periods, went into their shell slightly after losing a man and did not pursue attacking opportunities with their usual vigour.
"Probably our vision was a bit narrow," he said.
"That's a work-on for us because it's not something that's natural to us, but we allowed ourselves to get into that mode."
Flank Jerome Kaino said returning to Eden Park for the winner-takes-all third Test felt like the final of a World Cup – a tournament he has won twice.
"It definitely has that feel. The excitement we had at training today backs that up," he said.
"The Lions are a great side and there's a lot of history between these two teams, so being 1-1 it does have that feeling about it."
Kaino said there was "an edge" to the New Zealanders ahead of the game and they wanted to impose themselves while also maintaining discipline.
He was not concerned about a Northern Hemisphere referee – France's Romain Poite – being in charge of the match.
"We know how we can play physical and within the laws, so we'll just let the ref interpret how he wants to interpret and make sure we do our basics really well," he said.
The 80-Test veteran said a row between Lions prop Kyle Sinckler and some All Blacks after the siren in Wellington would not affect the hosts' attitude toward the match.
"I don't think it's our style to drag things off the field and carry it on. It just hinders what you want to do and how you want to improve," he said.
"There's always going to be feeling between these two team and when we cross those white lines we throw it out there, but once we leave I think we should dump it and not bring it into our preparation."