Newcastle's youngsters face the League Two outfit at Vale Park (kick-off 7.45pm GMT) in their final Northern Group D fixture but are unable to qualify for the last 32 following defeats to Macclesfield Town and Shrewsbury Town.
Cass, who has captained the under-21 outfit on multiple occasions this term, is hopeful his side can still use the game against the Valiants as a learning curve for the developing youngsters.
"You want to go in there and win against a senior side," the 19-year-old told nufc.co.uk. "There'll be a lot of experience gained if we could go and get three points against a League Two team.
"It'll be a tough game. We're expecting them to be very physical but if we can get the ball down and play our football then we'll hopefully be able to pass them off the park.
"We're going there hoping to try and progress from the game. We want to use this game as a stepping stone for when we play in the league. Our main objective is to try and finish as high as we can in the league and as far as we can in cup competitions. Although, we can't progress in this, we want to use it as momentum to keep going."
Due to a number of injuries, Newcastle's under-21 side have been depleted at times this term but Cass, who primarily as a centre-back, has been impressed with those who have stepped up from under-18 level.
The teenage defender is expecting a difficult encounter against senior opposition, with Port Vale heading into the clash on the back of an impressive FA Cup victory away to League One MK Dons.
"It's completely different to playing in a normal league game," the defender added. "It's more physical and the strikers know how to move you around especially when you need to know if you're going to win the ball when challenging for a header or something because they're bigger and stronger. It's a lot to learn which is good for us.
"When we're getting into those positions, we are unlucky but hopefully it will turn out different against Port Vale. In those final moments, we need to be calmer and if we can be more accurate with our play then we can get the right result.
"It's a young side at the minute because of a few injuries. The lads who are in the physio room are working hard to get back onto the pitch and those who have came into the team are doing very well. They're younger lads but it's all about getting experience and playing against men tomorrow will be another big step for them."
