Lambert's struggling side sit just three points above the relegation zone - albeit with a game in hand - and he is determined to seal their survival by securing their first victory in six games.
"If we win then it virtually gets us out of the relegation battle," he said.
"That's how big the game is. Everybody knows it. I said the other day that this is like a cup final and we're at home, with the backing of 38,000 people.
"That will have to drive us on as well and if the lads perform against a good side who have had a really good season then we'll do it.
"The ironic thing is that if we win, we can go above Hull."
When asked for his opinion on Gabriel Agbonlahor's claim that the clash was the biggest of the players' lives, the Scot added: "It's pressure and you deal with it.
"Gabby is saying that because they're still young. When they're 29, 30 years of age, hopefully if their careers keep going they'll have massive games to play in.
"I understand what Gabby is saying about it being a cup final, and that is how we have to treat it. You have to give it everything you've got and if you win then it puts everything out of the road."