The first third of this season has been a matter of simple mathematics for Sunderland. Unfortunately, they've been unable to solve the equation.
This Sunderland side can only do one of two things.
They either attack fluently and concede a shed-load at the other end.
Or they go ultra defensive, invite pressure on their goal and eventually concede, invariably by a self-inflicted error.
But they can't attack and defend effectively in the same game. The balance continues to elude them and Sam Allardyce is in a fire-fighting race against time to find it.
It was easy to see Allardyce's plan against Southampton - stay compact, put men behind the ball and then try to nick the points in the final 20 minutes.
Yes, it made for a dire spectacle and yes, Southampton looked by far the better side as they found space and enjoyed the lion's share of possession.
But that won't have necessarily phased Allardyce, particularly after seeing his back-line ripped to shreds at Everton six days earlier. It was a pragmatic game-plan.
Sunderland were indebted to a couple of smart saves from Costel Pantilimon and goal-line clearances from DeAndre Yedlin and Sebastian Coates, yet Allardyce's strategy was largely working, even if the Black Cats failed to muster a meaningful effort on goal.
But whenever Sunderland tried to be more defensive-minded under Dick Advocaat's stewardship, their hard work was invariably undone by a clanger and that pattern continued.
Ryan Bertrand was going absolutely nowhere, but Yann M'Vila - up till then one of the few Sunderland players showed some composure - committed himself to the most needless of tackles.
What does Allardyce do now?
He abandoned the orthodox strike partnership of Jermain Defoe and Steven Fletcher to give Sunderland greater solidity, but the Black Cats still ended up getting beaten.
Allardyce has two weeks to ponder his next attempt to find the right solution.
But with Sunderland now four points adrift of safety and losing any momentum gleaned from a derby victory (again) the outlook on Wearside remains desperately bleak.