It certainly will be for Scotland. After losing 13-12 to Argentina, Andy Robinson's men have to beat the 'auld enemy' at Eden Park to stand any chance of reaching the quarter-finals.
England can afford to lose the game providing they stay within seven points to earn a bonus point - but Johnson has punctured any notion of a safety cushion.
The England manager, who today recalled Delon Armitage, Courtney Lawes and Matt Stevens into the starting line-up, insisted his men approach the game as a do-or-die encounter.
Victory will ensure England top Pool B and face a probable quarter-final against France, rather than hosts and favourites New Zealand.
"It's knockout rugby. They're fighting for their lives and so are we," Johnson said.
"They have still got to win this week and the same for us. It's a huge game. If we get it wrong, it could be a boarding pass on Sunday night."
Neither Scotland nor England have ever failed to qualify for the knockout stages of the World Cup.
"You've got to have that (fear). When you are playing at this level, if you get it wrong you are going to get beaten," Johnson added.
"We know that, we have that realism.
"They are potentially dangerous, potentially vulnerable. They have to turn their frustration, their fury into a performance.
"It is the same for us, we have to get the right mindset. You could sense a certain edge in training yesterday, which is good.
"This is a full-on contest. Don't start worrying about 'if we get this and they get that', just go and win the Test match.
"We want to win the pool. We've got to try and beat Scotland. They're coming to take us on. Simple. The way it's always been.
"This is the oldest international in the world, there is a lot of history there.
"It's going to be tense, it's going to be nervy, there's going to be anxiety, it's going to be enjoyable. If I want a quiet life I can sit at home and watch it on TV."
Armitage has been preferred on the left wing to Mark Cueto, who had sparked England's victory over Romania with a quick-fire hat-trick but drops out of the 22.
Armitage missed England's Six Nations campaign after being suspended for eight weeks following a run-in with an anti-doping official.
But Johnson has been impressed with his form and dedication - and he gets his chance against Scotland with Cueto deemed to still not be 100% match fit after a back injury.
"Delon is in good form and he deserves another shot but it's tough on Mark. He got an injury at the wrong time," said Johnson.
"Obviously he is very disappointed. It was a tough call.
"Mark is a very experienced player who brings assurance, pragmatism and that real-world sense of what it's all about at this level.
"He has played in a World Cup final, he's been around for a long time and he's been a very consistent player for us. You know what you will get out of Mark in a Test match, it is high quality stuff and I said that to him.
"But you've got to make a call and Delon is in form, he's 100% ready to go and we felt that was the right selection."
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