Goals from Darren Ambrose and Jermaine Easter were enough to see Palace record their fourth win in ten days and continue their progress in the Carling Cup.
Palace took on high-flying Southampton at Selhurst Park with a place in the quarter-finals of the cup at stake and both managers ringing the changes from Saturday's Championship games.
Two of those Palace changes were Jonathan Williams and Jermaine Easter and they almost combined within the first minute but Saints keeper Bartosz Bialkowski was out quickly to smother the chance. It was the visitors though who went on to have the better of the opening 20 minutes with Lewis Price twice having to be alert to make good saves down low and Stuart O'Keefe heading off the line following a Southampton corner.
Jonathan Forte then showed his pace and strength to shake off Paddy McCarthy but drove straight at Price who saved well. Both teams looked comfortable in possession but failed to create anything of note until both Easter and Jonathan Parr almost broke through down the middle, Jack Cork doing brilliantly to get back and make the tackle.
The game moved into the second period but followed much the same pattern with packed midfields keeping the ball well but again not creating any chances. Jermaine Easter fired over from distance on 55 minutes and although Williams, Parr and Dean Moxey were linking well the Southampton defence kept Palace at arm's length.
The visitors young side hadn't created much of their own but Dan Harding's whipped ball across the face caused problems when it was met by Jonathan Forte, and the Eagles were relieved to see his header flash wide.
Then came the best move of the game when Williams quick feet enabled him to find Ambrose in the area and the experienced midfielder rolled the ball sideways to Easter, whose effort flew just wide.
That was a sign of things to come though as Palace soon took the lead. Ambrose's free-kick hit the wall but the ball eventually fell to Parr, his long-ball across the pitch was missed by two Saints defenders and came to Williams at the back post. The young Welshman fired the ball across the six yard box and Ambrose was left with the simple task of tapping in.
Williams was then tripped in the box by Dan Harding and won a penalty in an electric ten minute spell from the youngster. Easter it was who stepped up and sent the keeper the wrong way as Palace doubled the lead and made safe their place in the last eight.
Southampton didn't take the defeat lying down though and the introduction of Rickie Lambert almost provided a close finish when his free-kick was tipped over by the commanding Price. Palace held on comfortably in the end though and moved into the quarter finals for the first time in nine years.
Crystal Palace: 34. Lewis Price, 2. Nathaniel Clyne, 4. Jonathan Parr (16. Wilfried Zaha '84), 5. Patrick McCarthy (c), 7. Darren Ambrose (15. Mile Jedinak '75) 8. Kagisho Dikgacoi, 19. Jermaine Easter, 20. Jonathan Williams (6. Anthony Gardner '82), 21. Dean Moxey, 28. Stuart O'Keefe, 38. Peter Ramage
Subs Not Used: 1. Julian Speroni, 9. Steffen Iversen, 25. Antonio Pedroza, 29. Andy Dorman
Southampton: 21. Bartosz Bialkowski, 3. Dan Harding, 4. Morgan Schneiderlin, 8. Jack Cork, 12. Danny Butterfield (c), 16. Aaron Martin, 17. Jonathan Forte (9. Lee Barnard '69), 24. Lee Holmes (7. Ricky Lambert '77), 28. Ben Reeves (10. Guly De Prado '80), 30. James Ward-Prowse, 33. Steve De Ridder
Subs Not Used: 2. Frazer Richardson, 35, Corby Moore, 36. Jack Dovey, 39. Harlee Dean
Att: 11,865 (Away: 2,571) Referee Mr M Haywood