#1 Jose Mourinho needs to introduce an alternate gameplan in attack

As poor as United were going forward, they did create six clear-cut chances; headers missed by Messrs. Lukaku, Lingard, and Rashford (two)... the Matic shot which seemed to be going in but was prodded in by Pogba from an offside position... and the penalty that they should have got for handball by Maya Yoshida in the Saints box.
All really isn't doom and gloom, but United do need to work on alternate gameplans in attack. Mourinho generally trusts his on-field representatives to make the right choices int he offensive third of the pitch, but its apparent that no one apart from Paul Pogba has the nous to take a game by the scruff of its neck.
As the astute Soumalya Moitra noted with a tinge of frustration, Mourinho must soon realise that his current formation and method of attack have been worked out by the opponents... (yes, Jose can still point out that if United had taken all their chances in the previous three games, it'd be 9 points instead of a paltry 3... but such is life)... and a bit more possession, a bit more of an organised build-up might just be the way to go.
As it stands, United's position in the top-4 is under the most severe test.