Upson, who has 19 England caps, will start against Slovenia following an injury to Ledley King and the suspension of Jamie Carragher.
“It’s down to us as individuals to make sure we are in the right frame of mind,” explained Upson. “We have to let it flow, let it happen, hold nothing back.
“To focus on the result isn’t the answer for us at the moment. We need to focus on what we do, relaxing and playing football like it’s a Saturday afternoon in the Premier League, adopting the same kind of body language and temperament.
“If we do that we’re capable of getting a great result.
“You can’t go into it and freeze, you need to go in there with the attitude: ‘I’ve got nothing to lose, I’ll give it my best shot, let’s give it a rip’.
“Everyone has been committed from the start, but the problem has possibly been our approach to games and our mentality.”