Sadio Mané’s strike deep into stoppage time earned Saints all three points at Loftus Road.
Up until then Saints had endured an afternoon of frustration in west London as a battling Queens Park Rangers side held them for the majority of a keenly fought contest.
Against a team fighting for their lives to maintain their Premier League status, it had been a difficult task for the visitors to break down a laboured home team, but Mané’s timely intervention ensured that Saints got their rewards for never giving up.
Aside from Fraser Forster’s notable save on Charlie Austin’s close range flick, the hosts rarely threatened, but they did keep Saints at arm’s length.
The win came with a sour note attached to it as Saints lost Matt Targett to a serious looking neck injury which required the youngster to go to hospital as a precaution from his injuries sustained in a challenge with Matt Phillips.
This was Saints’ fourth win away from home match in succession, a new Premier League record for the club.
Ronald Koeman brought Sadio Mané, Matt Targett and Victor Wanyama back into the starting eleven, with Dušan Tadić among the substitutes. Ryan Bertrand missed the first match of his three game suspension.
Morgan Schneiderlin also returned to the squad and was named on the bench alongside Saints Academy midfielder, Jake Flannigan, who made his first appearance in a Premier League squad.
Saints got the game under way, defending the end housing the travelling support at Loftus Road and from the beginning Ronald Koeman’s men were the more assured looking team as they attacked a defensive Rangers side with purpose.
Early range finders from Eljero Elia tested ‘keeper Rob Green, though the Dutchman’s effort on seven minutes when he got on the end of Sadio Mané’s through-ball dropped agonisingly wide of the far post after Green was stranded as he rushed to the edge of his area.
Victor Wanyama drove a shot wide inside the area after Ward-Prowse’s free-kick delivery was cleared, but the hosts were able to snatch a shot inside the box when Joey Barton fired over from another cleared set-piece.
There was a break of six minutes after Targett sustained his injury in a mid-air challenge with Matt Phillips who appeared to lean in on the head of the youngster.
That saw the introduction of Florin Gardos, with Maya Yoshida moving across to left back, and thereafter, Saints took a little while to rediscover their rhythm, though they were soon creating chances again.
Mané tested Green after receiving a pass from Davis, and the Senegalese worked the ‘keeper again when he got on the end of Ward-Prowse’s delivery to force a corner.
From the resulting set-piece Saints went the closest they had come to breaking the deadlock when José Fonte clattered the crossbar with a strike from Ward-Prowse’s corner.
Not long after, Fonte was crucial at the other end in tidying up under pressure from Charlie Austin, while Taarabt’s strike from outside of the box was comfortable for Forster to gather.
In the second of seven minutes of stoppage time, Elia cuts inside to see a low shot saved at the near post by Green, and Elia was involved again at the end of the half when he was fouled by Richard Dunne for a free-kick which Ward-Prowse whipped narrowly wide to bring an action-packed opening 45 minutes to a close.
Saints remained the more likely looking team to strike first as they kept a solid shape, added to by the introduction of Morgan Schneiderlin on the hour mark.
Soon after his arrival onto the pitch Saints got their first opportunity of the second half when Pellè flicked the ball on into the area where Mané fired over with a wayward volley.
QPR replaced the tiring Taarabt with forward Mauro Zarate and the substitute’s first touch came inside the area when he clipped a close range shot at Forster, much to his and the home fans’ frustration.
Saints’ own struggles were starting to take a strain though, as they still couldn’t find a way through at the other end. Maya Yoshida took matters into his own hands with a strike from range which was held by Green, who then sliced a clearance into the crowd.
The hosts even went close to snatching the lead when Austin flicked on Barton’s rasping drive inside the six yard box only to be denied by a stunning one handed save by Forster to put the ball out for a corner.
Dušan Tadić was brought on with eleven minutes to play in place of the hard-working Elia as Saints rolled the dice again to try and force a winner.
With Rangers then forced into replacing defender Dunne who went of injured to be replaced by Eduardo Vargas, the two teams went like-for-like in the closing stages.
Zarate fired over a warning strike on 87 minutes which seemed to sum up the day, but deep into the four minutes of stoppage time, Saints eventually found their winner.
After the ball broke down the left side through Yoshida, it was over to Sadio Mané, who shrugged off Nedum Onuoha to fire a shot into the top right corner for the game’s decisive goal.
QPR had the ball in the net themselves late on, but an offside decision which was correctly given against them ensured the final whistle brought all three points with it.
QPR team: Robert Green, Armand Traore (Mauricio Isla 73), Steven Caulker, Clint Hill, Nedum Onuoha, Richard Dunne (Eduardo Vargas 83), Joey Barton (c), Leroy Fer, Adel Taarabt (Mauro Zarate 63), Matt Phillips, Charlie Austin
Unused substitutes: Alex McCarthy, Niko Kranjcar, Karl Henry, Bobby Zamora
Booked: Barton (14), Hill (58)
Southampton team: Fraser Forster, Nathaniel Clyne, Jose Fonte (c), Maya Yoshida, Matt Targett (Florin Gardos 26), Victor Wanyama (Morgan Schneiderlin 60), Steven Davis, James Ward-Prowse, Eljero Elia (Dušan Tadić 79), Sadio Mané, Graziano Pellè
Unused substitutes: Kelvin Davis, Harrison Reed, Jake Flannigan, Ryan Seager
Booked: Schneiderlin (75), Forster (90)
Goal: Mané (90)
Referee: Roger East
Attendance: 18,082 (including 1772 away)