It was a whirlwind start to the first period after Eric Bailly gave a penalty away four minutes in but Sergio Romero saved Manolo Gabbiadini's spot kick. Further chances from Bailly, Anthony Martial and Nathan Redmond followed, but remained goalless at the break.
The Saints dominated the opening minutes of the second period with Dušan Tadić, Jack Stephens and James Ward-Prowse going close but couldn't get past Romero. United looked to breath some life into their game with chances from Juan Mata and Martial, but could do nothing to prevent United's fifth consecutive league game without a victory.
Starting on a controversial decision
From the first whistle United did give an indication of disinterest ahead of next Wednesday's Europa League final, Southampton were looking to return to decent form at St Mary's and were handed a golden opportunity early on.
Bailly looked to take down the awkward high ball onto his chest but ended up striking his arm, replays showed that the Ivorian looked to be at least a foot outside the area but Mike Dean had already pointed to the spot. The Red Devils were given a shred of redemption as Gabbiadini stepped up, the Italian's shot was weak but Romero got down to palm away and give his confidence a big boost ahead of next week's final.
Bailly looked to redeem minutes later as he made rare bomb upfield, the defender cut in from the right after collecting the misplaced pass but it was straight at Fraser Forster who saved well with his legs.
Chances proved to be hard to come by
United's best chances of the first period came on the break and had another good chance in the 15th minute, it was brilliant from skipper Wayne Rooney as he took down the high ball and sent Martial through the middle. The young Frenchman did well with the run at Maya Yoshida, but he dragged the effort wide of the post from the edge of the box.
The rest of period went by without much to shout or scream about, but the Saints had the final say in terms of an opportunity with a minute to play in normal time. It was good from Redmond as he played a one-two with Steven Davis on the edge of the area, the winger's effort took a minimal touch from the returning Marouane Fellaini which took the pace off it and allowed Romero to collect.
Saints cranking up the pressure
Claude Puel headed into the clash under some increasing pressure as the board couldn't guarantee he would in charge next season, but his players looked fired up to help their gaffer as they bombarded United with a host of chances early into the second period.
The first came from Tadić as the home side set up the smart set piece, Ward Prowse dragged the ball back into the path of the Serbian who hit a sweet effort but Romero did well to punch the ball away.
Stephens was presented with an excellent opportunity in the 58th minute as the corner was headed towards him at the back post, the defender was left unopposed and with time to shoot but he managed to drag the effort back into the mixer and eventually cleared.
The best chance from open play fell to Ward-Prowse who was beginning to pull the strings for the Saints, he curled a sweet effort from the edge of the box but Romero did brilliantly to get across and palm it wide.
Starting to come into their own
Mata had stated ahead of the game stated that the side needed some momentum ahead of the trip to Stockholm, but United had barely troubled Forster but started to come into their own as the minutes began to tick down.
Again another opportunity presented itself on the counter attack as the ball was played through to Rooney, he did well to hold the ball up in the area before teeing it up for Mata but the Spaniard sent it over the crossbar.
Martial nearly drew first blood in what was an excellent individual effort in the 71st minute, he did well to make the run towards sliding in between defenders before taking the shot. It was dipping towards the bottom corner but clattered the base of the post, and Henrikh Mkhitaryan sent the resulting rebound well over the crossbar.