"I believe there is a time and a moment for players to deliver, and I believe it is Saturday," said the Manchester United defender, who is likely to start after recovering from a calf strain.
"If it is not I'll be talking to you on Saturday night and saying that you have found the measure of this team. There'll be no excuses.
"If we fail on Saturday then we have to hold our hands up and say, 'We haven't delivered, that the talk about us being potential world champions was rubbish.' So this is it for us."
Neville, who is widely viewed as the conscience of the team, believes history will take a dim view of the team if they fail on Saturday.
"We have to win if we want to be recognised as a great England team," the 31 year old said.
"If we don't we'll be recognised as a nearly team, a team that had potential but didn't deliver.
"The measure of this team will be in this tournament. We couldn't have had a better preparation. We're two games away from a World Cup final.
"Can we win the next two football matches? We have shown we can beat anybody on our day but now it's time for us to deliver.
"There is great expectation but it is an expectation that I think is right and correct and we shouldn't shy away from it."
Neville also admitted that the side has had a relatively easy run into the quarter finals and was aware they must improve if they are to continue in Germany.
"We sort of almost feel that we haven't been tested in a way, like we've played three or four friendlies," the former central defender said.
"To get to this stage without playing a massive match has been good in one way and in another way it makes us aware that we have to step up against Portugal and we have to perform."