After Saturday's 60-13 second Test win over Fiji, Foster said the series had produced growth in several areas.
"It's been a series where we've wanted to build some parts of our game. We've had to manage a few players from the last six months. We've had a couple of players come back from Japan, come out of quarantine, we've had a couple of long term injuries that have come back to play, and, I think, we've seen a little bit of rust in some of those guys.
"From that perspective, it has been great to get those guys back playing and I think that the way we've finished we've done some really clinical work that shows when we get the intention right we improve the quality of our ball carrying and a bit more knowledge in our structures we can actually get the speed of ball we want," he said.
Some defensive areas needed work but, after the three Tests, they were delighted with where they were.
Foster said Saturday's win had been a two-notch improvement for the All Blacks while Fiji had gone up one notch.
They started the game well and they had an improved performance from their bench in the last 15 minutes, but from the All Blacks' point of view, he was pleased with the patience shown during those stages and the way captain Sam Whitelock had led the team in maintaining composure.
There had been some turnovers against them in the first 20 minutes, but they had calmed down and played some clinical rugby.
"Our set-piece was strong, we missed a few lineouts early, but once we got going it was good. Our lineout and our drive and our play off that was really accurate, our scrum grew in confidence and put them under a lot of pressure, and our play off that was effective," he said.
The nature of the game at stages meant there wasn't a lot of phase play, and they had scored tries early in phases but, later in the second half, they were able to hold the ball for longer and benefit from that.
"Overall, the composure playing against a team that had exposed us last week in certain situations and I felt we supplied the remedy," he said.
After all the attention on the breakdown after the first Test, assistant coach John Plumtree said he felt the referees were tougher this week in that area.
"We put a bigger focus on our support being a little closer this week, whipping the jackelers out and once we sorted a couple of things out it got a little better. As they tired it was a bit easier for us but certainly when they were fresh they had great intent at slowing our ball down and stopping us from playing. Once we got that right we were away," he said.
As a unit, the loose forward trio of Akira Ioane, Luke Jacobson and Ardie Savea performed well in their respective roles, he said.
Foster said he was pleased with Rieko Ioane's effort on the right-wing. The opportunity to play him there had come earlier than expected.
"He's looking sharp Rieko, he looked really effective at wing and it was good to give him some minutes there," he said.
New hooker Samisoni Taukei'aho had been with the group for two weeks, and, in that time, he had been outstanding.
"He's done his homework. He backs himself and showed that he can be an accurate rugby player so it gives us some good options in that space," he said.
Hat-trick scorer Sevu Reece was in good form, was playing fast and energetic and was confident.
Captain Sam Whitelock said his decision late in the first half to take points on offer from a penalty chance came after they had tried lineout drives without success.
"There was scoreboard pressure, we were still up but it felt like we weren't getting reward for the pressure, so sometimes you're better off to take the three. It worked out quite well," he said.
Richie Mo'unga landed the penalty goal and, from the restart, they scored a try.
"It's quite nice when you can score in twos and get the scoreboard ticking over in that way," he said.