Saints dropped into the bottom three after the results on Saturday and they now take on a West Ham side that has won six out of the last seven games in all competitions, a tough task ahead if Saints are to pull out of the drop zone and a hero needs to emerge.
Saints start the game against the Hammers two points adrift of safety and know that anything other than a win will see them stay in the relegations zone for the trip to Bournemouth on Wednesday, however a win will take us up to potentially 15th or perhaps 14th leaping above West Ham themselves should we win by 3 goals.
That is how compact things are in the bottom half of the table, but by the end of next week things will be a lot more spread out and Saints have to make sure they aren't cut adrift.
But most of West Ham's good form is based on their performances at home, on the road they have won just once and lost the other three of their four games, scoring just twice, but the bad news is that they don't concede many, letting in just four in those games.
But they do have injury issues in their backline, Angelo Ogbonna tweaked a hamstring and Craig Dawson picked up a dead leg against Anderlecht on Thursday and both are likely to miss out.
Kurt Zouma could also be missing having been isolating with a virus issue although ex Saints loanee Michail Antonio looks likely to return after illness.
So although the Hammers are in a good run of form they are beatable and the hope is that the shock of dropping into the relegation zone will give Saints impetus to win the game.
Team wise Ralph Hasenhuttl needs to get out his best side with his best formation, that perhaps means a solid 4-4-2, the back four almost picks itself, KWP, Bella Kotchap and Salisu, the only question being at left back, does he go for Romain Perraud who I would contest is an able squad player, but not a 38 game a season Premier League player, or does he go for the youth of Juan Larios, who has undoubted talent, but little experience.
In midfield assuming that Ralph was not trying to flummox West Ham a little by saying that Romeo Lavia & Moussa Djenepo will not be in the squad through injury, i would go with JWP & Diallo in the centre with Stuart Armstrong on one side and then on the other he has a dilemma, does he go with perhaps Moi Elyounoussi,Joe Aribo or Maitland-Niles or even Adam Armstrong, it will be an interesting choice.
Then he has to find a partner for Che Adams up front from either one of those just mentioned or Sekou Mara.
Or does he mix the 4 -4-2 a little to a 4-2-1 3, this has been used with good effect at times and this might suit best the players he has to hand.
That means the solid back, JWP & Diallo holding with Joe Aribo just in front and then a striking trio which sees both Armstrongs on either side patrolling the wings with Che Adams in the centre.
This is going to be one of those games where we need a player to suddenly make his mark, perhaps that player could be Sekou Mara, I just have a feeling that he might be a key player today, perhaps from the bench.
But we can but speculate, what we need is Ralph Hasenhuttl to now show he knows what his best side is and more to the point those players to play to their potential, if that happens there is no reason why they shouldn't get all three points.
West Ham are a decent side, but they are not great, but they are organised and resilient and Saints don't like playing that type of team.
Hopefully having had a tough game against Anderlecht only 3 days ago will perhaps go in our favour later in the game, we have to play on that and even if things aren't going our way, know that they will tire as the game goes on.
Big big game for Saints, it's time now to get the season back on track.