A younger than usual Eagles outfit were swept away by league leaders Millwall who ran out comfortable winners at The Den.
With the majority of those Palace players not in international action featuring in a behind-closed-doors friendly at West Ham United 48 hours earlier, Gary Issott was forced to name five under-18 players in his starting line-up and they were fortunate not to fall behind after eight minutes.
Kyron Farrell and Alfie Pavey played a one-two on the edge of the box and the full-back picked out Paris Cowan-Hall at the back post, but he somehow managed to put the ball over from a few yards out.
But six minutes later the Lions did go ahead in similar circumstances. This time Jack Powell and Cowan-Hall linked up to put the ball on a plate for Lee Martin whose scuffed shot looped over captain David Gregory.
The Palace keeper was then forced into a low stop to prevent Paris-Cowan as Millwall found further joy down the left, and that was an area they exploited again on 21 minutes when Martin beat two players before finding Ed Upson who side-footed home from six yards out.
That prompted a nervy Palace into a response but Ben Wynter sliced an attempt well wide when he was well-placed before Jason Lokilo, Michael Phillips and Jacob Berkley-Agyepong all blazed over in quick succession.
But they made their pressure tell with seven minutes of the first half to go by pulling a goal back when Lokilo put a low centre across the face of goal and trialist Reiss Greenridge managed to scramble the ball home from close range.
Having done so well to get back into the game, the Eagles got off to a nightmare start to the second half by conceding seconds after the restart, as a long ball over the top caught Greenridge out and Martin’s tackle saw the ball balloon into the net.
Just before the hour mark things got worse when Martin played the ball to Ben Thompson who cut inside and blasted the ball past Gregory to add a fourth, but Lions keeper Ryan Sandford had to be at his best to deny substitute Connor Dymond’s free-kick and keep the three goal lead intact.
However they moved further ahead with seven minutes to go when some lovely passing in the final third cut through the Palace defence, and a neat touch by the influential Martin took the ball around Gregory and allowed Powell to blast it past to covering defenders to round off the scoring.
Millwall: Sandford, Romeo, Wood (Parr 46), Mbulu, Farrell, Upson, Thompson (Eze 70), Powell, Cowan-Hall, Pavey, Martin. Subs not used: Barton, Mulrooney-Skinner.
Palace: Gregory, Wynter, Phillips, Greenidge, Sturgess, Beimyr, Hoare, Dreher (Dymond 66), Berkley-Agyepong, Lokilo (Andrews 66), Bissaka. Subs not used: Perntreou, Croll, Coker.