Jordie Barrett's late penalty earned Foster's side a 19-17 victory over the Springboks that ensured the unbeaten New Zealanders reclaimed the Rugby Championship trophy with a fifth win in a row in the southern hemisphere competition.

The world's two top-ranked teams meet again on Sunday week on the Gold Coast to close out this year's Rugby Championship and Foster is setting his sights on a statement-making sixth consecutive win.

"Quite frankly, you go up to the Six Nations and if they win five games they celebrate it as a Grand Slam, and we've got that chance now in the Rugby Championship to have a grand slam opportunity next week," said Foster.

"For this group to actually put themselves in that position is massive credit to (captain) Ardie (Savea) and the men for the way they're gelling together and working hard.

"We know to achieve what we want to next week and get that grand slam we're going to have to lift a couple of cogs from tonight."

The All Blacks have dominated this year's Rugby Championship despite not being at full strength, with Savea serving as stand-in captain in the absence of Sam Whitelock while star halves Aaron Smith and Richie Mo'unga have also been sidelined.

Foster, though, believes his team are continuing to improve, though they were forced to battle hard to prevail against the Springboks' endless box kicking and ferocious defensive pressure.

"We are making strides on the physical side of the game and we are making some strides in our ability to deal with set piece pressure and how we go about it," he said.

"Clearly we're not the finished product yet, we know that. But I love the way we stayed in the fight and we problem solved and muscled up.

"We made that game a massive contest and an arm wrestle type of game that probably wasn't the game we wanted to have."

Foster praised the performance of fullback Barrett, who was safe under the Boks' high-ball barrage and perfect with the boot, kicking five from five including the winning penalty as the All Blacks won the 100th Test between the two nations.

"We knew it was a big game and there's a whole lot of reasons why it was big: the hundredth and the history of this competition between us," he said.

"They're a team we respect greatly and we've had a bit of the edge over them recently, but you saw how fine the margins are for us to deliver.

"Hats off to Jordie for that last kick. It was a tough kick."

Australian Associated Press