The young Red Devils got back to Manchester with a three-goal lead after a first leg win over Zalgiris.
The youngsters also became the first United team to play in the Baltic state of Lithuania.
Ethan Williams, Gabriele Biancheri, and James Scanlon all got on the scoresheet.
“It’s obviously a fantastic opportunity for all of us within the Academy,” coach Adam Lawrence told club media prior to the game.
“To be representing the club in this type of arena and this country is a fantastic occasion for us.
“Preparations have gone well, we’re looking forward to the game tomorrow, this is our last training session now.
“This is Europe’s elite competition at this age group. We want our players to get the opportunity to be playing against the best players in the best games. Naturally, this competition lends itself to that.”