Simpson, 33, said his side would enter the match with a genuine belief they could win it, despite losing the last five games.
He also said the Roos would benefit from a better lead-in to this clash with the Hawks, after being distracted by the 'chickengate' scandal ahead of round three.
"If anything, they're under the pump. Not us, like it was last time," Simpson told afl.com.au during the week.
"We've got nothing to lose. We could be playing anyone. It wouldn't really change how we go about it.
"We'll do a few different things and I think we've got a vastly different team in to when we played them last.
"That will be different, and the build-up to the game last time was all over the shop so we're a bit more stable this time around."
He believes the Roos will not hesitate against last year's premiers, despite the fact the Hawks will be out for blood after being humiliated by the Western Bulldogs last weekend.
"We're really not intimidated by playing anyone at the moment," he said.
"We've got our own agenda and we're disappointed from the weekend because we really thought we were in a position to win that game against the Swans.
"We're fired up as well."
Buddy Franklin and Jarryd Roughead booted nine goals between them in the round three 54-point win over the Kangaroos.
Simpson said he had faith in the side's young defenders to stop the dangerous pair, and called for the Roos' midfielders to lift their game and prevent the ball from getting to the twin towers in the first place.
"It was more the delivery. You get them one out and you kick to their advantage and they're pretty hard to stop," he said.
"It's more about the midfield pressure, I'd say, than the backline. We're pretty comfortable with them one on one, as long as it doesn't come in as clean as it did last time.
"Our defence has improved but it's still going inside their 50 too much.
"It's such a young group as well. Consistency will be the thing we're looking for. I don't think one particular area is overly concerning.
"We have a collective focus."
Simpson said the mid-season change in coach had been taken in a "positive light" by the players, and had renewed their energy with Darren Crocker's different take on their familiar processes.
He said the players were determined to register a win for the rookie coach, and were in the right frame of mind to do so.
"The game plan hasn't changed a hell of a lot. It's just a different person talking about it and concentrating on different parts of it," he said.
"That's been different. Darren couldn't come in and reinvent the wheel. It's just impossible to do that.
"He came in and kept the same structure but we're concentrating on a few different areas and I think it's been pretty positive the past couple of weeks.
"Basically, we just need a win."
