It was late heartbreak for Richard Shaw's young Eagles away to an experienced Millwall side on Friday afternoon.
A number of Paddy McCarthy's regulars in the under-18 squad featured at the higher level, impressing on their first appearance for the development side.
It was an evenly matched, physical bout between the energetic Eagles and the experienced home team, who featured former Palace defender Tony Craig in their ranks.
Mason Saunders-Henry struck early for Millwall, blasting an effort beyond Dion Henry from close range after being found in space. But despite the setback, Palace kept their composure and gave as good as they got in challenges across the pitch - making for an draining, but evenly contested, affair.
The front three of Joseph Hungbo, Andre Coker and Jason Lokilo had looked to cause Millwall's defence problems whenever the opportunity arose. However, the home side often sat deep and refused to allow the pacy trio space in behind to force an equaliser.
Half time came and went with the Eagles coming out for the second period still a goal down.
On the hour mark Hungbo and David Boateng were replaced by their under-18 teammates Ryan Hanson and Brandon Oddy, both of whom got stuck straight into the action, causing Millwall problems through the renewed energy brought to two thirds of the pitch.
However, it was another youngster who provided the moment to pull Palace back into the game. A twist and turn on the right saw Sean Robertson create enough space for himself to spot Andre Coker and Oddy in the box, towards the back post. His inch-perfect cross between the Millwall full back and centre-backs caused chaos for the home side and it was Coker who managed to react quickest, guiding the ball into the back of the net on 63 minutes.
There were few more chances as the game continued, but a late Millwall attack provided the killer moment. Kristian Brymora, found with space in the area, directed a low ball into the bottom corner on 89 minutes to settle the game.
Despite the scoreline, Richard Shaw was pleased with the performance, particularly given how many new faces there were in his matchday squad.
"I'm really pleased," he told Palace TV. "They were a team full of first team players and it's not just so much that, it's the inexperience of our side. We've got four under-18 guys making their debut today.
"That was a real tough game for us and I'm so proud of how hard they worked, the shape they played and the togetherness they showed. I just thought they were so unlucky [in the end], I thought a point would have been fair. That's what they deserved."
Millwall XI: Martin, Romeo, Craig, Tunnicliffe (Chesmain, 60), Cooper (Mbulu, 70), Rooney [c], Donovan, Thompson (McNamara, 87), Brymora, White, Saunders-Henry.
Millwall subs: Sandford.
Palace XI: Henry; Brown, Woods [c], Tavares; Robertson, Husin, Boateng (Hanson, 60), Daly (Mitchell, 73); Hungbo (Oddy, 60), Lokilo; Coker.
Palace subs: Funnell, Matthews.