Too many influential first choice players missing, too many individuals below par, too few correct decisions in possession and too little experience on the bench was too much to overcome.
Chalking it up to the absence of a handful of talismanic figures would not be unreasonable. Yet concerns of underlying issues lingered a little too heavily in the air even before kick-off to be disregarded entirely.
First to the absentees. Leeds supplying Brazil with a new star came at an expected cost. The club were adamant at the start of the international break that their winger would be back in the UK and available for Southampton and they were right on one count, he was there.
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But when the team sheet was produced, the man who lit up the Arena da Amazônia in the early hours of Friday morning was not on it.
A sparkling 71-minute performance on his full international debut, complete with a pair of goals, a 36.5 hour window and 15 hours of flying made it too risky to play him in Bielsa's eyes.
No Raphinha, no problem? The Whites are far from a one man team, Bielsa has other options and simply turned to two long-time favourites, Jack Harrison and Daniel James.
There are always star players, Kalvin Phillips has become one under Bielsa and while issues arose when he was absent, it took a squad to escape the Championship and finish in the top 10 of the Premier League.
The problem comes when Phillips joins Raphinha in the St Mary's stands, and when top goalscorer of the last two seasons Patrick Bamford is missing. And when Junior Firpo, the Barcelona left-back you signed to replace Gjanni Alioski, is also out. And when Robin Koch and Luke Ayling are recovering from surgery.
Bielsa has never been one for excuses - the most you'll get is a nod in the general direction of the difficulty lots of concurrent injuries in one area of the field brings - and times like this are when his small squad philosophy and reliance on the Under 23s is forced to prove itself.
At St Mary's it failed the test and it was alarming how quickly it became apparent that Leeds were going to struggle.
They couldn't pass out from the back, not so much because Southampton pressed with intensity, they just took up positions that removed almost all forward options for the Leeds man on the ball.
A pattern developed whereby Illan Meslier would pass to one of his three centre-backs, they would find their wing-back on the touchline and he would look up to see Mateusz Klich surrounded, so the ball either went backwards or aerial.
Ralph Hasenhuttl predicted a scrappy game and both sides looked intent on proving him right. Leeds in particular looked like they'd all flown back on the red-eye from Manaus.
It wasn't always a lack of viable options that prevented them from getting their passing going, goalkeeper Illan Meslier was wayward with a couple of early diagonal balls, but even when he did find a blue shirt, there was little or no fluidity to the visitors' attacking game. Players stumbled, first touches bounced on a few yards, the touchline became a ball magnet.
When Southampton began to settle and create chances, things quickly worsened for Leeds. By the 30-minute mark, Meslier's goal had been peppered by nine shots and Leeds had not registered a single one, on or off target.
It took 45 minutes for the visitors to create even an opportunity to have a crack, Tyler Roberts' neat turn taking him away from three men only for the shot to go wide. It was a rare example of bravery on the ball. They wore the right colours but they did not look at all like Leeds.
The saving grace of a desperately poor first half was that Southampton were unable to take advantage and find the net, often bizarrely eschewing a shot or killer ball for a backwards or sideways one, taking extra touches that let Bielsa's men off the hook.
A look at the Argentine's bench at the break showed Adam Forshaw as the only player of any seniority, and him not having played a league game for more than two years.
Bielsa stuck with his starting XI and they did at least stem the bleeding somewhat. Harrison found his dancing feet to work space for a shot that deflected up over the bar to give Leeds a corner and a little spell of pressure, only for the Saints to march straight upfield to take the lead.
Armando Broja's counter attack goal came in the 53rd minute but felt for all the world a winner.
It was to Forshaw that Bielsa then turned, withdrawing a completely ineffective Rodrigo and pushing Roberts up front with Klich behind him. The substitute tried to get on the ball and inject some urgency but soon discovered the problem that pre-dated his introduction, a lack of options making him look sloppier in possession than he maybe was.
Somehow, an ill-deserved equaliser almost arrived, James' pace catching Mohammed Salisu napping, the winger nipping onto the ball at the edge of the area and turning it past the post with only Alex McCarthy to beat.
Joe Gelhardt came on for a late Premier League debut and Crysencio Summerville replaced Roberts in the final 10 minutes but Leeds never came close to creating a chance. The performance got exactly what it deserved and six points from eight games puts United fourth from bottom.
The injuries might clear up and might do so quickly, but other serious problems like players failing to match last season's form, what has started to feel like an over-reliance on Raphinha in the construction of successful attacks, the lack of goals and assists from both record signing Rodrigo and Roberts and a midfield that has lacked control in too many games, might not.
The answers have to come from within.
A failure to sign a midfielder who improved the first team during Forshaw's two years out is being seen in a harsher and harsher light as this season goes on but January business is, as ever, unlikely. The bed is made and right now it's not comfortable so restlessness is to be expected. Bielsa won't rest and nor, you expect, will his players until solutions present themselves and the major discomfort is once again felt by opponents and not Leeds.
But whether or not this was just one of those days, there cannot be too many more like it.