The All Blacks found themselves 10 points down in as many minutes at the start of the game but came back to win 22-16.
Henry said there were a lot of guys who had not played for a while and they were a bit rusty and it took them a while to get into the game.
"Guys got back to the backbone they've had in recent times and played with huge character. We got better as the game went on," Henry said.
"We should get better. We've got a foundation to build on and some of these players had not played for a number of weeks, so they should get better as the Tri-Nations goes on."
Henry said the substitutions made in the second half were mainly tactical and he praised the athletic ability of replacement prop Owen Franks.
"But what we are finding with the great physical contest that we have out there [is] that you need 22 players to play and they all have to be of a good standard."
He said Piri Weepu had developed into a fine impact player, who could turn tests.
He also praised the performance of halfback Jimmy Cowan, who he said had one of his better tests.
Captain Richie McCaw said he was pleased with the side's composure to come back as the side had barely got out of second gear in the first 20 minutes and then in the final 20 minutes basically squeezed the Wallabies out of the game.
"It wasn't that pretty but we just didn't give them many options. But when you look at it, we were 10-0 down and then to come back and pretty much shut them out in the last 20, that is pretty encouraging," McCaw said.
He did not rate his own performance that highly but said as the game went on, he got a better feel for the game.
"But you look at the whole team performance and we won, so that's great. As for my own game there is room for improvement."
Henry said two tests in South Africa was a huge challenge.
"I'm sure we'll galvanise to the challenge. We will look at this as a series. They [the Springboks] have played some big time rugby recently against the Lions and they'll be ready."
The team flew out to Africa early yesterday, though two of the 30 players have been left behind as only 28 can travel.
Loosehead prop Wyatt Crockett and wing Hosea Gear were told they were not required shortly before the All Blacks headed to South Africa.
The requirement to leave the pair behind clearly irked Henry.
"I don't understand the rules," he said.
"It's something to do with money, I guess. We are frustrated we can only take 28."
Crockett, who made his test debut against Italy three weeks ago, was surplus to requirements as he can only cover one side of the front row.
Three hookers are standard for a trip to South Africa, meaning Aled de Malmanche was essential to back up Andrew Hore and Keven Mealamu.
Gear, another one-test rookie, lost out to Isaia Toeava although the utility back is managing a foot stress fracture.
Wallabies coach Robbie Deans said his side was much better than last year but it was frustrating to lose.
"It is a work in progress. But clearly we are getting better. We'll just keep going. It is a habit you've got to acquire but it is coming," Deans said.
Deans said it was frustrating prop Al Baxter was penalised three times but he declined to elaborate.
