The Black Cats lead Manchester United heading into the second leg, thanks to a 2-1 win at the Stadium of Light earlier this month, putting them on the verge of a first trip to a major final since 1992.
Many of the Sunderland players have never reached a major cup final before, and Poyet knows that chances to do so are limited for the smaller club.
"I always say that," said Poyet. "There are plenty who have never had this opportunity, either because they are too young or because they have been playing in teams that didn't have the chance to reach this possibility.
"That's why we need to make sure that we do everything possible to give those players the chance to feel what it means to play in a final at Wembley and have the opportunity of winning a trophy.
"People think it's easy to get to a semi-final and a final, but you don't get it every year and that shows you how difficult it is, apart from the top teams who normally are close. It's a great opportunity."
The match gets underway at Old Trafford at 7.45pm.