Match ends, Crystal Palace 0, Southampton 1.
Crystal Palace slipped closer to the relegation zone as Jay Rodriguez earned Southampton victory at Selhurst Park.
The England striker chased a poor Jason Puncheon headed backpass to challenge Palace goalkeeper Julian Speroni and turn the ball into an empty net.
Rickie Lambert also struck the post for Saints as Palace failed to create a clear opening with their direct style.
Yannick Bolasie drew a save from Artur Boruc, as the Eagles ended the day only two points above the bottom three.
Tony Pulis's side had taken 10 points from 18 before Saturday to bolster their survival hopes but home defeat, coupled with Cardiff's win over Fulham, means they are far from safe.
The Eagles have never survived a season in the Premier League and, on 27 points, are 10 adrift of the tally that was enough to stay up last year, with 10 games remaining.
Without the injured Marouane Chamakh, Palace frequently aimed long balls at Glen Murray but the tactic drew a blank, and they are now the top flight's lowest scorers with 19 goals.
Southampton centre-backs Dejan Lovren and Jose Fonte coped consistently with the hosts' long balls and throw-ins - though the former might have been fortunate not to be sent off for a foul when he looked to be the last man.
It was actually during Palace's best spell of pressure in the first half that Southampton got the decisive goal, Rodriguez pouncing for his 11th league strike of the season.
Puncheon's poorly judged header saw Rodriguez race clear and, after a sliding challenge on Speroni, he rolled the ball home.
The goal sparked life into the contest and Lambert controlled a poor headed clearance from the impressive Adam Lallana's cross to volley against the post with Speroni beaten.
Three years ago this weekend, Lallana and Lambert were playing against Yeovil in League One, but the England pair were at the heart of their side's good work as Southampton consolidated ninth place in the table.
A Bolasie strike from 18 yards on the stroke of half-time, saved by Boruc with his legs, was the closest the London side came in the first period.
And it was Bolasie again, powerful and busy throughout, who was at the heart of the game's most controversial moment when Lovren, who appeared to be the last man, upended him 20 yards from goal.
The Croatia international received only a yellow card from referee Howard Webb, who was a central figure in the second half as a series of fouls made for a disjointed contest.
But, flanked by full-backs Luke Shaw and Nathaniel Clyne, Lovren and Fonte dealt well with the physical presence of Murray - and the introduction of substitutes Thomas Ince and Cameron Jerome - as Palace failed to score at home for the sixth time this season.
Chelsea, Manchester City and Liverpool are all yet to visit Selhurst Park, and Palace travel to 18th-placed Sunderland next Saturday knowing they will need to find goals from somewhere if they are to stay clear of trouble.
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- 15JedinakBooked at 57mins
- 13PuncheonSubstituted forInceat 66'minutes
- 8DikgacoiSubstituted forJeromeat 66'minutes
- 7BolasieSubstituted forThomasat 83'minutes
- 2ClyneBooked at 88mins
- 4SchneiderlinBooked at 66mins
- 6José FonteBooked at 45mins
- 5LovrenBooked at 48mins
- 8DavisBooked at 55minsSubstituted forWard-Prowseat 89'minutes
- 18CorkSubstituted forWanyamaat 34'minutes
- 7LambertSubstituted forGallagherat 75'minutes
- Howard Webb
- Shots on Target
Second Half ends, Crystal Palace 0, Southampton 1.
Foul by Luke Shaw (Southampton).
Cameron Jerome (Crystal Palace) wins a free kick in the defensive half.
Corner, Crystal Palace. Conceded by Jay Rodriguez.
Offside, Crystal Palace. Mile Jedinak tries a through ball, but Cameron Jerome is caught offside.
Substitution, Southampton. James Ward-Prowse replaces Steven Davis.
Nathaniel Clyne (Southampton) is shown the yellow card for hand ball.
Hand ball by Nathaniel Clyne (Southampton).
Morgan Schneiderlin (Southampton) wins a free kick on the left wing.
Foul by Cameron Jerome (Crystal Palace).
Offside, Crystal Palace. Jerome Thomas tries a through ball, but Cameron Jerome is caught offside.
Attempt missed. Jose Fonte (Southampton) header from the centre of the box misses to the right. Assisted by Adam Lallana with a cross following a corner.
Corner, Southampton. Conceded by Dean Moxey.
Victor Wanyama (Southampton) wins a free kick in the defensive half.
Foul by Jerome Thomas (Crystal Palace).
Substitution, Crystal Palace. Jerome Thomas replaces Yannick Bolasie.
Adam Lallana (Southampton) wins a free kick in the defensive half.
Foul by Dean Moxey (Crystal Palace).
Foul by Luke Shaw (Southampton).