Labuschagne's first-over failure was one of several low points in Australia's 176-run series-deciding loss in Cape Town on Sunday, as the tourists were all out for 111.
Brought to the crease after just three balls, he attempted to hit his first from Kagiso Rabada through the legside and had a leading edge through the gully for four, before leaving the next outside off.
Labuschagne tried to do the same to the next delivery, was hit on the pads and given out lbw.
He reviewed, but ball-tracking showed umpire's call with the ball clipping off-stump, leaving Labuschagne to trudge off at an even slower rate than normal.
Some would suggest Labuschagne was a man fighting for his career in the final-day chase. Realistically, that battle was lost long ago.
The Queenslander had cut a forlorn figure in the lead up to the decider, to the point where it almost appeared he may have already been dropped.
Labuschagne carried that tentative nature into his first innings and edged Simon Harmer to slip for a fifth-ball duck.
The numbers are not pretty for Labuschagne.
His run of 49 innings without a century is the longest ever for an Australian top-four batter.
Where once he averaged 60.82 through his first 30 Tests to be the top-ranked batter in the world, he has averaged 28.43 in the 38 matches since.
Labuschagne was dropped for the West Indies last year, but recalled for the home Ashes after four games in the Sheffield Shield.
A longer stint now looks necessary. The concern for Labuschagne is that it could be permanent.
Had this been a home summer, Labuschagne would likely have been dropped by now.
He will certainly be gone for the first Test against New Zealand in Perth in December.
Australia's selectors had been keen to keep their faith in the 32-year-old, given his history and potential to take the batting forward in a post Steve Smith era.
Speaking before Cape Town, George Bailey also pointed to the balls Labuschagne had soaked up during a run of starts at No.3, helping players around him.
But the fear of former players is that they may have burnt him in the process.
"That's the job of the selectors to realise you have a player nowhere near his best. How do you get him back to his best?" Simon Katich said in SEN commentary.
"Their opinion is 'we'll keep picking him'. It's been very obvious to everyone watching this series they've got this horribly wrong.
"What they've got more horribly wrong is they've potentially crucified a bloke's career. And that's what they have to live with now.
"He might not come back from this. It would take a huge amount of fortitude and mental strength to go away, get his game back in order and get his spot.
"Because there might not be a spot. Who knows?"
