The Boks will meet their archrivals, the All Blacks, in successive Rugby Championship Tests in Auckland and in Wellington on 6 and 13 September, in matches that will be crucial in both teams' campaigns, with only two points separating them on the standings after two rounds.
The New Zealanders currently lead the standings with six points, while the Wallabies are one point behind with five, followed by the Springboks and Argentina in third in fourth place on four points, with four matches remaining.
History is firmly on the side of the hosts, as the Boks last won a match in Auckland in 1937.
"I haven't tracked everything since 1937, but for us the important thing will be to go out there and play our game - Springbok rugby - and play our best game," said Flannery.
"I think we've been a little inconsistent so far this season. We've had some really good performances, especially against the Barbarians and in our second Test against Italy, but I don't think we've really hit the heights that we are looking for yet, so we need to be at our best."
Zooming in on their defence, the former Ireland international was optimistic that the Boks were working on plans to counter the challenge ahead, especially given the fast-paced game and quality individual players within the All Blacks setup.
"We conceded more tries than we would have liked to in the first Test against Australia," said Flannery.
"We definitely overplayed a bit in that match (which the Springboks lost 38-22), which took some juice out of our legs, but we feel we have good plans going into the matches against New Zealand."
Flannery added: "It's difficult to say how much more different our defence will have to be against New Zealand compared to what we did against Australia, especially since they have individuals with an X-factor, and we have to be prepared for that.
"We went well against them last year, and we're relatively settled this year, so there's a lot of consistency there, which means we have to defend individuals, while they've also tightened up the way they play by mauling a lot more, and that's going to be something we have to work on.
"From our perspective, our maul defence hasn't been where we want it to be yet, so in general, they have really good individuals, who we'll have to defend within our system, and their maul is going to be a challenge for us as well."
The Springboks had their second training session of the week on Saturday, following their arrival in New Zealand a few days ago, and will have Sunday off to rest and recover fully from the trip to the land of the long white cloud, before switching into full Test match mode on Monday.