From the doghouse to the penthouse, Aaron Smith ended his test match week significantly better than the way he started it, as the All Blacks beat the Springboks 21-11 in Dunedin tonight.

Chastised and penalised earlier in the week after breaking a curfew following the scrappy victory over Argentina in Wellington, the little halfback responded in the best manner possible.

He came off the bench where he'd been demoted to following his Wellington indiscretions and the 23-year-old home-town Highlander imprinted himself all over another combative, competitive test match against the old enemy from South Africa.

But for Smith's magical try midway through the second half, the New Zealanders might have struggled to secure the victory they did, two tries to one, to all but secure the world champions the inaugural Rugby Championship title.

The Manawatu halfback brilliantly sized up the situation from a ruck 20-odd metres out, spotted big Flip van der Merwe in front of him, slipped round him with ease and had the skill and the gas to leave the cover defence for dead and finish with a glorious dive.

"The ball popped out and I just sort of reacted. I saw a big guy flying to my right, stepped him and the crowd went 'boom'," said a rapt Smith afterwards. "I saw space, I saw a guy coming from my left and I just stepped. I reckon the crowd got me there, it was really loud and  I was pretty knackered.

"I was very happy it all worked out. When I ran off to side and dove I thought 'geez, I could run that under and made the kick a lot easier for Aaron'. When Azza put the kick over I was a lot happier because knew I could have been in trouble for running off to the side as well as for showboating a bit.

"As you could tell I was pretty pumped up, I had a point to prove, and I was very happy when I got over try-line."

That took an 8-8 deadlock to 15-8 and when Boks replacement prop Dean Greyling was sinbinned soon after for a horrible cheap shot on Richie McCaw at a ruck, it was always going to be a long haul back for the South Africans.

They briefly threatened when a Johan Goosen penalty got them back to within four, but two Aaron Cruden penalties iced a victory for the All Blacks that was every bit as hard-earned as it looked.

Skipper Richie McCaw was huge for the New Zealanders, demonstrating all his qualities in his 110th test. Luke Romano had another impressive outing in the black jersey up front, while Israel Dagg - the other try-scorer on the night - Cory Jane and Aaron Smith off the bench all showed their class on a night when clear-cut opportunities were few and far between.

But what about those South Africans? Supposedly in some form of disarray they competed hugely, led by their big, hard-running loose forwards and the brilliance of Bryan Habana, and were unfortunate not to have secured another famous win on Kiwi soil. A poor kicking game, out of hand and at goal, cost them dearly.

If they are indeed in rebuilding mode, on the strength of this it may not be long before we see them back near their best.

The Boks would have been kicking themselves after missing a gilt-edged try chance in the fifth minute when a Francois Hougaard toe-through should have served up a try wide on the right to Habana. When ball was shifted right only a shocking final transfer denied the visitors a certain five-pointer.

That ended up being the story of the first 40 minutes for the South Africans who should have taken a lead into the sheds, but instead trailed 5-3 after Morne Steyn missed three of his four shots at goal, and Frans Steyn was astray with two more from long range.

The All Blacks did score the only try of the half just shy of the 20-minute mark courtesy of a fabulous counter-attack strike. Dagg was the scorer, after featuring four times in the movement, though two quite brilliant offloads by Sam Whitelock and Kieran Read created the opportunity.

But, frustratingly, that was the only clear opportunity carved by the New Zealanders over a half where they played a clear second fiddle to the South Africans.

The suspicion that Piri Weepu might paya  price for a less than assertive first 40 was confirmed when Smith ran out for the second half at halfback. Soon after, Keven Mealamu and Brodie Retallick also entered the fray.

But not before a piece of Habana brilliance put the Boks 8-5 in front after the wing sliced through in the first receiver's position and then put in a  perfect chip-and-chase at full tilt.

You could sense at that stage the All Blacks needed something special to turn the tide. Thankfully they got it from a young man who faced his challenges this week, but responded magnificently.

New Zealand 21 (Israel Dagg, Aaron Smith tries; Aaron Cruden 3 pen, con)

South Africa 11 (Bryan Habana try; Morne Steyn pen; Johan Goosen pen)

Ht: 5-3.

- © Fairfax NZ News