The Red Rose have already beaten Australia and Argentina this month, but were criticised for taking their foot off the accelerator against the Pumas in the second half, adding just one converted try to a 24-6 half-time lead.
Launchbury feels that England will have to prove that they are they best in the world if they are to get the better of a formidable New Zealand pack.
"I think first and foremost we're happy with the win last weekend," said Launchbury. "But at the same time we felt we had a very strong first half and played some great rugby and perhaps in the second half we didn't reach those heights again.
"This weekend it's about us and if we manage to start well we've got to continue to play well. I think the first 20 minutes after half time is massively important to us, we need to come out of the blocks at half time firing. I think we're happy with the way things are going, the scrum and the lineup, at the same time we obviously understand the challenge we have this weekend, New Zealand are a formidable pack and they've got some great players.
"I'd like to think we've proved over the last season that it wasn't a fluke and we've gone on and won lots of close games. We won some tough games away from home in the Six Nations and various things like that. We're immensely proud of what happened last year but this is a new game and a new task. We're going to need to be on it for 80 minutes to stand in with a chance. It's a massive opportunity for me and the team, when you get to play a southern hemisphere side in back-to-back weeks like we've been doing, to play the best team in the world, the number one side, it's a great challenge."
England inflicted the All Blacks' only defeat since winning the 2011 World Cup the last time they met at Twickenham in December.