The two-legged tie is evenly balanced after an entertaining 2-2 draw last week with Jesse Lingard and Will Keane on the scoresheet for the Reds.
Paul McGuinness' side will be hoping for a similar performance to the one that accounted for Chelsea 4-0 in the semi-finals in front of an expectant crowd. The Blades will be backed by a large travelling contingent as another exciting occasion seems guaranteed.
Eric Harrison, who famously coached the fabled Class of 92, is in no doubt that lifting the coveted trophy would provide a major boost to the current crop of promising prodigies.
"If they go on to win the FA Youth Cup, and I hope they do over these two legs, it'll give them massive confidence," Harrison explained to ManUtd.com.
"It'll give them a massive lift - they're not daft and know the history of the Youth Cup. If they can win it, believe you me, they'll go up a few notches."
Tickets are still available at Old Trafford and the match is also live on MUTV with Gary Neville providing co-commentary.