Match ends, Southampton 3, Crystal Palace 1.
Southampton 3-1 Crystal Palace
Late goals from Maya Yoshida and James Ward-Prowse earned Southampton victory over Crystal Palace in an entertaining game at St Mary's.
With seven minutes to go, Japan defender Yoshida tapped into an empty net to put Saints 2-1 in front, before Ward-Prowse slotted in a Cedric Soares cross moments later.
Christian Benteke had given the visitors a first-half lead, finishing a superb team move from close-range.
Nathan Redmond levelled in controversial circumstances for the hosts on the stroke of half-time, volleying in Steven Davis' cross after the Southampton skipper had appeared to barge Wilfried Zaha off the ball.
Both sides looked set for a point apiece, before the late drama which moved Southampton nine points clear of the relegation zone.
Despite four wins on the bounce before facing Saints, including a surprise victory at leaders Chelsea on Saturday, Palace remain deep in relegation trouble - three points above the bottom three.
Should Saints' leveller have stood?
The game-changing moment just before the break left Palace's players incensed, with Zaha having to be restrained by his team-mates as the teams headed down the tunnel at half-time.
Davis' seemingly heavy challenge on the Ivory Coast winger saw a number of Palace players protest towards referee Roger East, but Saints played on and Redmond coolly finished past a static defence.
However, Palace may have been fortunate to get away with two penalty shouts just before the equaliser.
The ball appeared to strike Jeffrey Schlupp's hand as Dusan Tadic tried to take it past him and Shane Long went down under a clumsy challenge from Luka Milivojevic.
Long, recalled in place of Jay Rodriguez, was a menace throughout but looked rusty in front of goal, missing several opportunities including an effort that went inches past the post after 40 seconds.
But it mattered little in the end, in a game which saw 42 shots in total, thanks to two goals inside a minute.
Yoshida pounced on some slack defending to stroke in Jack Stephens' clever pass for his first league goal of the campaign and Ward-Prowse finished coolly from the centre of the box.
Palace's nightmare run-in
Palace boss Sam Allardyce will surely be livid his side failed to hold on to what could be a crucial point in their battle against relegation.
Of their eight remaining fixtures, five are against the current top six, along with a home game against in-form Leicester.
Their final two matches of the season at Selhurst Park could be pivotal in their survival - with relegation rivals Burnley visiting on 29 April and Hull on 13 May.
One plus point is the form of Benteke and Zaha who once again pulled the strings in attack.
Zaha showed great balance and trickery in the build-up to Palace's goal, fooling three defenders before the ball worked its way out to Andros Townsend who left the Belgian striker with the easiest of finishes.
But the pair could not conjure a way past a resolute Saints defence for the remaining hour and Palace fell to their 17th loss in 30 league games.
Man of the match - Nathan Redmond
Southampton manager Claude Puel: "I think we could have had three penalties by half-time. I'm happy because our players kept on going and found a solution at the end. I'm happy with the squad, and the quality and the result.
"We were physical and strong and it was important against this team."
Crystal Palace boss Sam Allardyce on the incident leading up to Saints' equaliser: "It was grievous bodily harm. The assistant referee is totally out of order not putting his flag up - not just 100%, about 200%.
"Wilf [Zaha] doesn't get the protection he gets, everybody knows that, Wilf's just blatantly bowled over right in front of the assistant referee - he can't put his flag up for whatever reason, you need to ask him and hold him responsible for the Southampton team to get the opportunity to get the equaliser."
'Allardyce's first Premier League loss at St Mary's'
- Saints have lost just one of their last 14 home league meetings with Crystal Palace (W10 D3), winning the last six in a row.
- This was Sam Allardyce's first ever Premier League defeat away to Southampton at St Mary's (W2 D6 L1).
- Southampton have won 63% of their Premier League games against Crystal Palace (10 of 16); their best win rate against a side they've faced 10 or more times.
- Christian Benteke has scored five goals in his last five Premier League games versus Southampton, three of those coming for Crystal Palace.
- Nine of Benteke's 11 Premier League goals this season have been away from home.
- Nathan Redmond has scored six Premier League goals this season; his joint-best return in a top-flight season (also 2015-16).
- Three of Maya Yoshida's four Premier League goals have come against sides from London (one vs Crystal Palace, two vs West Ham).
- James Ward-Prowse has scored more Premier League goals in 2016-17 (4) than in his previous four seasons combined (3).
Southampton travel to the side one place above them in eighth, West Brom, on Saturday, while Crystal Palace host Arsenal in a London derby at Selhurst Park on Monday (20:00 BST).
- 2Cédric SoaresBooked at 79mins
- 8DavisSubstituted forHøjbjergat 87'minutes
- 14RomeuBooked at 71mins
- 22RedmondSubstituted forRodriguezat 90'minutes
- 31SchluppSubstituted forDelaneyat 58'minutes
- 7CabayeSubstituted forSakoat 45'minutes
- 28MilivojevicSubstituted forFlaminiat 88'minutes
- 17BentekeBooked at 88mins
- Roger East
- Shots on Target
Second Half ends, Southampton 3, Crystal Palace 1.
Corner, Crystal Palace. Conceded by Oriol Romeu.
Foul by Jay Rodriguez (Southampton).
Joel Ward (Crystal Palace) wins a free kick in the defensive half.
Offside, Crystal Palace. Jason Puncheon tries a through ball, but Bakary Sako is caught offside.
Foul by Dusan Tadic (Southampton).
Joel Ward (Crystal Palace) wins a free kick in the defensive half.
Corner, Crystal Palace. Conceded by Fraser Forster.
Attempt saved. Jason Puncheon (Crystal Palace) left footed shot from outside the box is saved in the top right corner.
Foul by Maya Yoshida (Southampton).
Wilfried Zaha (Crystal Palace) wins a free kick in the attacking half.
Substitution, Southampton. Jay Rodriguez replaces Nathan Redmond.
Foul by Pierre-Emile Højbjerg (Southampton).
Wilfried Zaha (Crystal Palace) wins a free kick in the defensive half.
Substitution, Crystal Palace. Mathieu Flamini replaces Luka Milivojevic.
Christian Benteke (Crystal Palace) is shown the yellow card for hand ball.
Hand ball by Christian Benteke (Crystal Palace).
Foul by Sam McQueen (Southampton).
Wilfried Zaha (Crystal Palace) wins a free kick on the right wing.
Substitution, Southampton. Pierre-Emile Højbjerg replaces Steven Davis because of an injury.
Goal! Southampton 3, Crystal Palace 1. James Ward-Prowse (Southampton) right footed shot from the centre of the box to the bottom left corner. Assisted by Cédric Soares.
Attempt blocked. Andros Townsend (Crystal Palace) right footed shot from outside the box is blocked. Assisted by Christian Benteke with a headed pass.
Goal! Southampton 2, Crystal Palace 1. Maya Yoshida (Southampton) left footed shot from very close range to the bottom right corner. Assisted by Jack Stephens.
Attempt missed. Jack Stephens (Southampton) right footed shot from the left side of the six yard box is close, but misses to the right. Assisted by Nathan Redmond.
Delay over. They are ready to continue.
Delay in match Steven Davis (Southampton) because of an injury.
Corner, Southampton. Conceded by Damien Delaney.
Attempt blocked. Steven Davis (Southampton) left footed shot from the centre of the box is blocked.
Attempt blocked. Steven Davis (Southampton) right footed shot from the centre of the box is blocked. Assisted by Shane Long.
Nathan Redmond (Southampton) wins a free kick in the defensive half.
Foul by Wilfried Zaha (Crystal Palace).
Cédric Soares (Southampton) is shown the yellow card for a bad foul.
Foul by Cédric Soares (Southampton).
Bakary Sako (Crystal Palace) wins a free kick in the defensive half.
Attempt saved. Maya Yoshida (Southampton) header from the centre of the box is saved in the centre of the goal. Assisted by James Ward-Prowse with a cross.
Corner, Southampton. Conceded by Wayne Hennessey.
Attempt saved. Oriol Romeu (Southampton) left footed shot from outside the box is saved in the bottom right corner.
Attempt missed. Mamadou Sakho (Crystal Palace) header from the centre of the box is high and wide to the right. Assisted by Bakary Sako with a cross following a corner.
Corner, Crystal Palace. Conceded by Maya Yoshida.