Watson (pictured) said experience had taught him that the All Blacks were not invincible.
"I was never too fazed by the whole mystique of the All Blacks," he told media in Tokyo.
"I respect the prolonged success they've had as a team, but the whole aura that surrounds them and the invincible stuff – I never bought into that.
"They are rugby players and we're rugby players. We work very hard and they work very hard. They are definitely beatable. They are humans at the end of the day.
"There'll be 23 of them and 23 of us on Saturday. They're human beings and rugby players just like us. So we've just got to do what we can do and play our best rugby," he said.
His experience as part of the 2017 Lions series, and especially the win over the All Blacks in Wellington, gave him some additional belief, but it didn't change his basic mindset, he said.
"I believe I had that mindset before; that they are beatable. The boys came close to beating them in November," he said.
Avoiding being spooked by the All Blacks' reputation would be crucial.
"I think the mental part of the game is definitely massive. We won't let the occasion dictate anything to us.
"I thought we did that very well last weekend, managed by our leaders like Owen Farrell, Maro Itoje and Mako Vunipola. Guys like that were on it all week and it will be the same again this week," he said.
Meanwhile, England's only Rugby World Cup-winning coach Sir Clive Woodward said in The Daily Mail the game was 'probably the biggest match and biggest rugby occasion in the modern history of the English game – and that includes our World Cup triumph in 2003'.
"England against the All Blacks is the classic confrontation. Every rugby fan around the world wants to see it – indeed, every sports fan is up for this. What's more, both sides are bang in form.
"And on top of that is the novelty value of this fixture. We haven't seen it at the World Cup in 20 years and indeed the sides have only met once in the last five years in any sort of game. That was at Twickenham last November when England started brilliantly but blew a 15-0 lead to lose 16-15," he said.
While they hadn't played each other regularly, modern technology meant they would know nearly everything about each other.
"There will be no gifts from New Zealand. England will have to earn and manufacture every single point they score on Saturday. That's going to be extremely tough but the good news is that this England team is getting better with every match and has enormous strike power.
"New Zealand are always confident, it's part of their rugby DNA, but let's be clear here: England are the side they would have least wanted to meet in the semifinals. They know England have the power to hurt them," he said.