The Springboks fell to a shock 49-0 defeat to Australia at Brisbane on Saturday, the resurgent Wallabies triumphing by a surprisingly large margin.
The New Zealanders have already defeated their Bledisloe Cup rivals on home soil this season. But Henry said form will count for nothing in game three of the series at WestPac Stadium.
He told The Press: "We just have to prepare right. It's important we have our own standards (because) we don't know what South African team will turn up on Saturday.
"Their pride will be deeply hurt so they will be a much better side on the weekend.
"It doesn't matter which side we play, we just have to maintain our standards. It was a disappointing game on the weekend and I'm not sure why that is, but I imagine they will play a lot better."
Henry names his team on Tuesday, and has a fully-fit squad to pick from.