With an average age of 21, the side included eight Academy players with another four on the bench as the manager shuffled his pack with Wednesday's European showpiece on the horizon.
Phil Jones and Wayne Rooney were the only players over 23 in the team, and the boss's young selection put on a show to sign off a disappointing league campaign with a much needed win.
Josh Harrop joined an elite group of homegrown players to score on their league debuts for the first team, with James Wilson and Marcus Rashford also both having done so in recent seasons.
The 21-year-old hit a hat-trick for the Reds Reserves earlier in the week, and followed that up impressively with a solo goal and man of the match showing on his senior bow.
Harrop also became United's 100th different Premier League goalscorer with his stunning solo strike to put United ahead on 15 minutes.
There was youthful vim and vigour all over the park with the two full-backs, 20-year left-back Demi Mitchell and 19-year-old Tim Fosu - Mensah, particularly impressive.
Fosu - Mensah enjoyed a breakthrough campaign last term but has seen his progress stunted by a lack of minutes and injury this time around.
His season looked to be over after he picked up a shoulder problem in the derby, but he returned against Palace to stake a late claim for inclusion in the Europa League final squad.
Mitchell, on the bench against Spurs and Southampton recently, was excellent on his debut and shackled the pace and trickery of Palace winger Wilf Zaha throughout.
Having made brief cameo appearances off the bench earlier in the season, there were first starts for 20-year midfielder Scott McTominay and goalkeeper Joel Pereira, also 20.
McTominay had come on for the closing minutes of the 2-0 defeat to Arsenal, while Pereira got a taste of senior football as a substitute in the 4-0 FA Cup win over Wigan in January.
With the match won and one substitute left, Old Trafford witnessed a piece of history with the introduction of 16-year-old Angel Gomes in the closing minutes.
The London-born but Salford-raised youngster became United's third-youngest debutant, behind Duncan Edwards and David Gaskell - and the club's youngest ever in the Premier League era.