Goals from Joel Ward and Wilfried Zaha edged the Eagles into the FA Cup fourth round as they knocked Southampton out of the competition for the second season in succession.
Ward popped up with his third goal of the season just before the half-hour mark to put Alan Pardew’s men ahead at the break, but an equaliser by Oriol Romeu pulled the Saints level just after half-time.
However a well-taken strike by Zaha settled the tie in Palace’s favour, although they had to endure a late onslaught as the hosts squandered three late chances and hit the post in the final minutes before Palace’s passage was secured.
Southampton started brightly with the plan seemingly to put balls in behind the Eagles’ defence for Shane Long to latch onto, which succeeded in the third minute but after rounding Wayne Hennessey a sliding block by Damien Delaney prevented his former international teammate from scoring.
Steven Davis then steered a header wide when he was well-placed to put the hosts in front, but they would continue to control proceedings and Romeu was next to try his luck but saw his 25 yarder deflect wide off Joe Ledley.
However having been under the cosh for the majority of the first half an hour, Palace took the lead on 29 minutes with their first meaningful attack of the game. A misplaced pass in midfield allowed former Saint Jason Puncheon to bring the ball forward and get into the penalty area, and after he cut the ball back for the onrushing Ward the ex-Portsmouth man found the net once again back on the south coast.
That lifted Palace and they nearly doubled the lead when another delicious delivery from Puncheon fell kindly into the path of Scott Dann, but he couldn’t quite get the contact he wanted onto the corner and glanced the chance wide.
Romeu then had a golden opportunity to restore parity just before half-time when some intricate passing on the edge of the box allowed Long to lay the ball off to the Romanian midfielder but he saw his shot deflect over the bar when the net should have been rippling.
Chasing the game to keep his cup dreams alive, Ronald Koeman threw caution to the rather blustery wind swirling around St Mary’s by throwing on Dusan Tadic and Juanmi at the interval, and the attacking approach paid dividends just six minutes after the restart. Hennessey managed to keep out a powerful strike by Cuco Martina, but Romeu was in the right place to force the ball home from a few yards out and tie the cup tie up once again.
With the Saints once again finding themselves in the ascendancy at the start of the half, Hennessey dirtied his gloves again when a snapshot by Tadic in a congested area forced the Welshman to get down low and push his effort away, while Palace went close through a substitute of their own when Bakary Sako attempted to find the top corner with an audacious free-kick from way out on the touchline and was fractions away from doing so as it dropped wide.
But Palace get themselves back in front on 68 minutes. Puncheon again found himself in a good position on the left and struck the ball towards goal which looked destined to be nestling into the top corner but for a terrific save by Maarten Stekelenburg, however it fell kindly for Zaha who lashed the rebound into the empty net on the volley in front of the ecstatic 4,500 travelling Eagles fans.
The visitors were once again chasing the game and Hennessey made a carbon-copy stop to thr one that denied Tadic earlier to thwart Juanmi, but then the visitors had to withstand three big chances in the final few minutes which somehow all stayed out.
Firstly Romeu saw a header spilled by Hennessey on his goalline but Dann was on hand to clear the danger, and from the resulting corner Jose Fonte’s header was deflected millimeters over for another set-piece, and from that one a crashing header from Virgil van Dijk struck the post and deflected wide as Palace breathed a sigh of relief.
But their spot in the fourth round was only secured after Hennessey diverted a fine bending free-kick from James Ward-Prowse around the post in the dying seconds as Pardew’s side kept their cup hopes intact.
Southampton: Stekelenburg, Martina, van Dijk, Fonte, Yoshida (Juanmi 46), Targett, Romeu, Clasie (Ward-Prowse 76), Davis (Tadic 46), Mane, Long. Subs not used: Gazzaniga, Cedric, Reed, Seager.
Palace: Hennessey, Ward, Dann, Delaney, Souare, Cabaye (Jedinak 83), Ledley, Zaha, Mutch (Sako 57), Puncheon, Campbell (Chamakh 76). Subs not used: Speroni, Kelly, Hangeland, Lee.