The Saints came back from behind to put a torrid run to an end. They pipped Burnley 3-2 at home through fitting replies from Stuart Armstrong, Danny Ings and Nathon Redmond.
Ralph Hasenhuttl would have expected his side to finish in the top half of the table, but a barren spell of form has left them lurching just above the relegation zone.
Even then, they are on 36 points, knowing a win against the Baggies would all but secure their status in the top flight.
Meanwhile, West Brom are on the back of one of the most sensational displays in their Premier League history. They smashed five past Thomas Tuchel's Chelsea in a 5-2 display.
While it was a jaw-dropping performance by Sam Allardyce and his troops, there's still a lot of work to be done as they are eight points off 17th-placed Newcastle.
There is no doubt West Brom will fancy their chances and hope to get the job done at full throttle against an unpredictable Southampton outfit.
West Brom vs Southampton head-to-head
Not much separates the Baggies from Monday's visitors, as Southampton have won 32 games as opposed to West Brom's 24. Not to mention, 24 matches between the two teams have finished as draws.
Of late, however, Southampton have held the upper hand with wins against West Brom in each of their last four Premier League matches.
West Brom form guide (Premier League): W-L-D-L-W
Southampton form guide (Premier League): W-L-L-W-L
West Brom vs Southampton team news
Sam Allardyce will hope Dara O'Shea can shrug off the injury he endured against Chelsea last week. Meanwhile, former Blues right-back Branislaw Ivanovic's long-term injury is set to keep him on the sidelines.
Conor Gallagher, who could not play against his parent club, is poised to return to the starting XI.
Injuries: Branislav Ivanovic
Hasenhuttle reported that the Saints will assess Kyle Walker-Peters' situation ahead of the game, as he suffered a knock while training. Elsewhere, Oriol Romeu, William Smallbone and Michael Obafemi remain long-term absentees.
Injuries: Oriol Romeu, William Smallbone, Michael Obafemi
Doubtful: Kyle Walker-Peters
West Brom vs Southampton probable XI
West Brom predicted XI (5-4-1): Sam Johnstone; Darnell Furlong, Dara O'Shea, Kyle Bartley, Semi Ajayi, Conor Townsend; Matthew Phillips, Okay Yokuslu, Conor Gallagher, Matheus Pereira; Mbaye Diagne
Southampton predicted XI (4-4-2): Fraser Forster; Kyle Walker-Peters, Jan Bednarek, Jannik Vestergaard, Ryan Bertrand; Stuart Armstrong, Ibrahima Diallo, James Ward-Prowse, Theo Walcott; Nathon Redmond, Danny Ings
West Brom vs Southampton match prediction
The Saints appear to have finally found their rhythm in the English top-flight. It may be difficult for West Brom to muster another result against a direct, purposeful team in their uphill battle for Premier League safety.
Southampton should get over the line, with Danny Ings expected to be the difference maker.
Prediction: West Brom 0-2 Southampton