Two first-half goals from Sean Robertson (pictured)guided Palace's Under-18 side to a battling victory over rivals Millwall despite playing with 10 men for the entire second half.
In a fiercely competitive match, which saw many yellow cards handed out, Robertson's brace put the Eagles in control before the Lions pulled a goal back almost immediately.
Brandon Pierrick, who was excellent throughout on his full debut at this level, did well to beat his man down the right on 12 minutes, but saw his cross blocked, before a second opportunity allowed him to pick out Robertson who placed the ball in the back of the net with a composed finish from six yards.
With 26 minutes on the clock, Robertson had his second. Pierrick and David Boateng combined to play him in behind the defence and he again finished superbly to double the lead.
But Millwall hit back instantly with a half volley after a cross from the right eluded Tariq Ossai, and left Rohan Luthra with no chance in goal on his full debut.
An off the ball incident saw another debutant in Cian Trehy shown a straight red card for violent conduct, before the game found an edge with strong challenges going in. But Palace went in to the break leading their rivals.
The second half was played with less intensity than the first, but the Eagles defended resolutely. Luthra saved well with his feet but the rebound fell to a Millwall player, only for Drew Matthews to make a goal-saving block.
Despite severe pressure towards the end, Palace could even have increased their lead, and Robertson nearly had a hat-trick but saw efforts saved, whilst Pierrick was also denied by the goalkeeper.
Palace dropped back to preserve their lead and weathered the storm from the Lions to hold on to a fine victory in the final league game of the season as the Southern section league champions stretched their unbeaten run to 10 games.
They will face a play-off clash at home to either Leeds or Bolton from the Northern section for a chance to be crowned overall league victors in the final should they win.
Palace: Luthra; Ossai, Matthews, Trehy; Russell, Hanson, Boateng, Malcolm; Pierrick, Street, Robertson
Goals: Robertson 12, 26
Sent off: Trehy 38.