The 10 minutes after halftime, when Jerome Kaino was in the bin, were crucial, he believed.
"Everyone stepped up a gear and we just kept holding them out. The South Africans didn't offer much on attack and just played the territory and kicking game they do so well."
He said Kaino was unlucky to be sent for 10 as was Bryan Habana but was happy the referee showed consistency.
"The Habana card sealed it," he said. It was a tough task to pick a man of the match.
"Ben Smith's high-ball recovery was outstanding as was Kaino's brutal defence.
"I also thought Ma'a (Nonu) was good until he came off."
Looking ahead Mr Paerau predicted the All Blacks would meet the Pumas for the first time in a World Cup final this weekend.
"I think they'll get up against Australia. Their game against Ireland was at another level - but we will obliterate them in the final."
He said All Black coach Steve Hansen had run his side "meticulously" during the tournament and they were now peaking at the right time.
Springbok supporter Bernard du Toit switched on the TV at his Napier home long before the birds rose to watch his beloved team.
He said it was a good contest between the two fierce rivals.
"I'm just glad after last week against France the All Blacks didn't run away with it."
He said he was proud of the performance from the Boks players and they could leave the tournament with heads high.
"I thought Schalk Burger was fantastic all tournament with his tackle count and running metres.
"We are a young team and I think our midfield especially stood up against the experienced All Black centre pairing."
Mr du Toit said with the All Blacks playing 70 per cent of the game at the right end of the field the Boks could find no way through the staunch Kiwi defence.
With half-Kiwi kids and a Kiwi wife, Mr du Toit's allegiance will shift to the men in black for the final on November 1. "I'd rather see New Zealand go back to back than for Australia to win it!"
Shed 2 duty manager Kat Spooner said the atmosphere was so quiet you could have heard a pin drop.
"Wasn't that intense? I've never seen so much focus on a game."
She said the only sound heard over the commentary was the click of the coffee machine as all eyes were glued to the screen.
A crowd of "well over 100" included two brave Springbok fans.
"Those two went home disappointed but it really could have gone either way.
"It wasn't like the French game when you knew early on France weren't going to go anywhere."
She said the room "roared" after Dan Carter slotted what proved to be the match-winning drop goal. Ms Spooner said she had already received bookings for next week's final.
"Groups are wanting to book the same tables and do it all again!"
Extra seats were required at Hastings' Focal Point Cinema as All Black fans packed the theatre a Springbok supporter stood among the sea of black shirts.