Villa are currently in the bottom three but victory at the Britannia Stadium will leave them only one point adrift of the Potters, who have won only one of their last 11 games.
Lambert has seen Villa climb put of the relegation zone on four previous occasions this season and takes heart from the performance levels and confidence shown by his players in recent weeks.
He said: "When you look at the table, from 11th place down only four points separate the teams down to us. That's nothing. It's basically just one game.
"Everybody has to play some really hard fixtures. It's how you hold your nerve. We try to keep the place upbeat and we don't look like a team that is playing with nerves.
"You have to have a strong mentality so the pressure doesn't get to you and see it through. If you do that, that's half the battle.
"I have not spoken about relegation or anything like that. I think that breeds negativity. Form gives you confidence and we are playing well enough to get results.
"The thing for me is that they are confident in having the ball. It is not as if they are frightened by it and just want to launch the ball up the field. They are certainly play with a bit of freedom."
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