Southampton's latest run of four games has yielded just two points from a possible twelve and any lingering hopes of promotion are sliding away with each match.
Defeats away at Norwich City and Oxford United highlighted some of the key tactical and stylistic problems that Southampton have. Those problems extend far beyond the key issue of playing three at the back but that is the simple change that could make the most difference throughout the second-half of the season.
In theory, there is nothing wrong with playing within the structure of a 3-4-3. It allows a team to keep possession well and draws the opposition forward which in theory creates space behind. The stats back this up at Southampton.
They have completed the highest percentage of passes (81.6%) and moved the ball further around the pitch than any other team in the Championship. Mostly these passes have gone across the back three.
Two ways opposition teams have beaten Saints' approach
Knowing this, opposition teams have either pressed more aggressively or sat back and let the defenders have the ball, engaging them once they have reached a certain position in the field.
Coventry City took that one step further until they went down to ten men. They were content to allow Nathan Wood and Jack Stephens to pass the ball between them - but as soon as the ball got to Taylor Harwood-Bellis, the forwards closed him down quickly.
The reason for this is two-fold. Firstly, Harwood-Bellis has showed that he is able to execute a telling pass if he is given time on the ball to do so. The movement of the Southampton front three is so good that Harwood-Bellis has repeatedly been able to find Finn Azaz and Adam Armstrong with key passes.
Secondly, when Harwood-bellis has been pressured his decision making has become flustered and he has selected the wrong pass, like the one he made in the 47th minute on Monday night which put Caspar Jander in all sorts of problems and led to the free-kick from which Birmingham scored.
What Southampton must do now is simple and obvious
To put this right, Southampton must switch to a system that gives their defenders more forward passing options. In essence this would require a switch from three centre-backs to two and the selection of attacking full-backs who can both attack and defend.
Elias Jelert demonstrated that he can be very effective playing as a wing-back. In turn, this could free up Tom Fellows to play in a more advanced role, either as an orthodox right winger, or on the right side of three attacking midfielders playing behind the striker.
Stylistically, switching to four at the back should not impact on the manager's desire to pass the ball out from the back. Central defenders can still split either side of the penalty box in possession and Gavin Bazunu is good enough with his feet to cope with receiving the ball under pressure.
The differences that making the switch to four at the back would make are obvious. For too long, Southampton have relied on Tom Fellows and Léo Scienza carrying the ball forward from deep areas and drawing fouls to progress up the pitch. Jelert showed on Monday that passing and moving is equally effective and forces the opposition to turn and run back towards their own goal.
Southampton's great strength is in the attacking players that it has at its disposal. To get the best out of these players, Southampton need to attack more often and play with the ball further up the pitch. It is time for the back three to go and the sooner Tonda Eckert realises that the better it will be for Southampton's promotion chances.