England tackle France in the quarter-finals at Auckland's Eden Park on Saturday, immediately after Wales clash with Ireland in Wellington. The winners will meet in a mouthwatering semi-final.
On Sunday, Tri Nations champions Australia meet South Africa for a chance to face either New Zealand or Argentina in the last four.
Of all those ties, Johnson reckons only the Pumas can be considered outsiders. The rest are 50-50, which makes for arguably the most exciting World Cup yet.
"It's do or die, isn't it? It's a World Cup quarter-final. You've got to start big. There's no holding yourself back for anything," Johnson said.
"I think more than ever it is anyone's tournament.
"New Zealand are still obviously very strong. The loss of Dan Carter is a big blow, but they're still a very strong all-round team.
"But it's a fascinating tournament. Every game this weekend is going to be interesting.
"You probably couldn't have said that four years ago - although you wouldn't have thought England would have got through the quarters and made the final.
"I think it's going to be a tough game for Argentina but you can see seven of them getting there."
England's minimum target is an appearance in the semi-finals and Johnson sprung a significant surprise when naming his side to play France.
The England manager opted to start with Jonny Wilkinson and Toby Flood together for only the second time in his tenure, stressing it was an "exciting combination" and not a "gamble".
Johnson had previously abandoned plans to use a second playmaker in favour of a powerful ball carrier after experimenting with the likes of Olly Barkley and Shane Geraghty at inside centre.
But England have chosen this week to reverse that policy in a selection which mirrors in many ways what Clive Woodward did before the 2003 semi-final, also against France.
The week before that game, Mike Catt had come on to help Wilkinson as England struggled against Wales and was retained in the team for the semi-final at inside centre at Mike Tindall's expense.
Last week, Flood was sent on and played a decisive role as England battled to victory over Scotland and he too has been retained at inside centre at Tindall's expense.
Tindall has been struggling with a dead leg but had England been desperate to use the Gloucester centre, Johnson confirmed they would have.
Flood will offer England an alternative kicking option and far improved midfield distribution, which should have strike runners Ben Foden, Chris Ashton and Mark Cueto salivating at the prospect.
Eight years ago, Woodward felt Catt could offer the same thing.
"We went out with a game plan to play a bit wider. Our coaches thought their forwards were so strong but after 15 minutes we realised we needed be bit more direct. We got on top of them and turned the screw," Johnson said.
"Toby does offer something different (to Tindall or Shontayne Hape).
"It's an exciting combination for us. It gives us Toby's kicking game, Toby's passing game. He's a pretty experienced Test player now, 40 plus caps. He's been playing well.
"It's not a gamble. You always put a lot of thought into your selections - no more so than when you're in a World Cup quarter-final.
"Mike took a couple of bangs last week and hasn't really been available to us this week.
"That was part of the equation - Mike's injury and Toby playing very well."
The last time Flood lined up alongside Wilkinson was in the opening game of the 2010 RBS 6 Nations, when England beat Wales having seen Hape and Riki Flutey pull out in quick succession.
Hape, Matt Banahan and Tindall, whose main quality is force in attack and a strong defence, have all started at inside centre since that day.
"It's one of the options we've got," said Johnson. "It does give us some different things that we can do on the field when we play those guys."
Wilkinson has struggled with his goal-kicking through the tournament and his return of nine from 20 shots is the worst of the World Cup.
Wilkinson and Flood will make a final decision after tomorrow's kicking session at Eden Park as to who will take the responsibility against France.
"You go into a game like this, I don't think you'd want to be playing against Jonny Wilkinson," said Johnson, mindful no doubt of how France were put to the sword by Wilkinson's boot at the 2003 and 2007 events.
Johnson made three other changes to his side with lock Tom Palmer preferred to Courtney Lawes, Nick Easter replacing James Haskell at number eight and Mark Cueto in for the suspended Delon Armitage.
"I said in front of the team that it's a particularly hard call on James. He didn't deserve it in terms of how he's played," said Johnson.
"The big thing is what Nick brings us - he's actually a very good aerial player, very powerful on the carry and good in the tight situations.
"He'll give us good direction but it's tough on James."
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