The second half burst into life from the outset, with Everton threatening to take the lead just two minutes after the restart.
Ceiran Looney raced through one-on-one, but Benetton was quick off his line to produce an excellent save, marking an impressive first stop of his U21s career.
Five minutes later, Looney made way for former Everton first-team midfielder Tom Davies, who almost made an immediate impact. His clever pass looked to release Braaidan Graham, but Walker-Smith raced across to make a superb sliding clearance.
Palace soon began to threaten at the other end. Benamar drove into the area after being released down the left channel by Williams, but his low and hard strike from a tight angle was gathered by the 'keeper.
The Young Eagles then passed up two excellent opportunities through Williams...
First, Kalembo sent a dangerous ball across the face of goal, but Williams could only turn agonisingly wide of the far post. Moments later, a defensive mix-up presented him with a golden opportunity from close range, but he was unable to convert.
He would not have to wait long for redemption, however. Adams-Collman lifted a teasing delivery into the area, Gibbard headed the ball into Williams' path and the forward, stretching to reach it, prodded a volley into the far corner to give Palace the lead.