Manchester United went into the clash in third place and a staggering 15 points behind leaders Manchester City, with Jose Mourinho's men in need of a win to get their title bid back on track. Or, at least, pile some pressure on their city rivals. Quite the contrary, Pep Guardiola will be rubbing his hands at the possibility of opening the gap to 17 points at Crystal Palace.
The Saints seemed like the perfect opponent, in dismal form with four defeats in their last seven league matches. But you never know in Premier League football.
All signs pointed to a home win, but an early blow complicated plans for United. Romelu Lukaku clashed heads with Hoedt and was carried off on a stretcher with a head injury, with Rashford coming on for the Belgian. It all came after an early interchange between both sides with Lukaku himself wasting a sitter when he headed over the bar from close range.
After a five-minute stoppage and a bit of worry around Lukaku, the game got back underway and the hosts settled on the ball. Pellegrino's Saints were still a constant threat, with Ward-Prowse forcing David De Gea into action. The visitors certainly played with more confidence than what you would expect from a team with one win in the last 11 matches.
The majority of chances fell to the hosts, with Paul Pogba pulling the strings from midfield. The Frenchman displayed passing and strength with some world-class cameos in the middle of the park, but his teammates were not quite up to task in the final third. Southampton goalkeeper McCarthy managed to keep everything out before the break and a penalty appeal was waved away by the referee when Lingard's ball appeared to come off Yoshida's arm inside the area.
The second half got underway and the visitors seemed to take a step forward. While the home side's football gained urgency and lost fluency, Southampton revelled in the spaces awarded by United's need to press forward in search of an opener. De Gea was once again superb, denying a first-time drive from Shane Long by sticking out a leg to turn it over the bar.
With the clock ticking, the hosts' frustration grew and Southampton defended deep in their own half, easily dealing with the long balls and crosses as United piled bodies forward. Mourinho will believe his side should have been awarded a penalty in the first half, and he will certainly not be happy about Pogba being flagged offside when he put the ball in the net.
United's captain for the day poked home Matic's ball on the line, which may have been heading in off the post if the Frenchman hadn't intervened, but Richard West correctly disallowed the goal. Mourinho looked furious as he disappeared into the tunnel, with the result leaving the Red Devils 15 points behind City, who have a game in hand. It feels like game over in the Premier League.