Sheffield United's lack of pride in mauling by Newcastle United was the most worrying aspect
History has shown that newly-promoted sides can be on the receiving end of beatings from time and time. Even if 8-0 is a tad heavy.
The south coast club proceeded to then go on a six-game unbeaten run and ended the season in 15th position.
The real worry for the Blades was the way they totally lost their shape, structure and discipline without the ball against Newcastle.
As bad as their defending was, the sight of their midfield totally capitulating and letting Newcastle run amok was equally as damning.
For all of the undoubted quality that the Magpies possess on an individual level, their success was based on something which was far from spectacular. The foundation was built around good, honest graft.
After making the breakthrough in the 21st minute, Newcastle won nearly every first and second ball and outworked, outran and out-tackled their opponents for the rest of the game. That is what would have really pleased Heckingbottom's counterpart Eddie Howe and hurt his rival.
It's something that Sheffield United did on a consistent basis last season under Heckingbottom and during their seasons of plenty under Chris Wilder.
Uncharacteristically, there was no pride in their performance from Sheffield United on Sunday, which was so unlike them.They got beaten on home soil to a side stacked with more talent than Newcastle in Manchester City last month. That they made life distinctly uncomfortable for the European champions and produced a performance without the ball which was pretty textbook was something.
On Sunday, players abrogated those responsibilities. That was the thing that Heckingbottom could not stomach, not the losing, as painful as it was.
He commented: "We understand the league we are in and have lost three points.
"So long as we learn from the nature of the defeat and what has gone wrong, three points is all we have lost.
"But there were moments when Newcastle outfought and outran us and that is not acceptable.
"Our game and season won't be defined by this game. We have been competitive in games and we could and should have had more points. But the moment we step off it, that (Sunday) is what can possibly happen."
"We were 3-0 down at half-time and that was purely down to our organisation when the ball was out - the first goal was from a throw-in, the second one from a corner and the third from a wide free-kick. It was the organisation that cost us.
"We set up more attacking and aggressive. We wanted to cause them as many problems as they caused us. They scored from three restarts and then we are on the back foot.
"We made changes to block up the middle of the pitch, but there wasn't that same level of determination in the second half.
"Mistakes lead to goals and we made far too many in the second half and they led to chances and goals. The things we have to put right are the bits off the ball."
United do possess character in their ranks, of that there is no doubt. They showed a strong jaw last season to clinch promotion despite having plenty thrown at them at regular junctures.
At one spell last autumn, they took just three points from six winless games, for instance. They would also suffer a wobble late in the winter. They got over it.
Unfortunately, the Premier League is a different kettle of fish. Heckingbottom's biggest test awaits.
If his United side are not at least hard to beat, like they were against City and Spurs, then they have nothing.
While the way in which the Blades' midfield was bypassed for two-thirds of Sunday made for gruesome viewing, the defence surely remains the major concern.
Their lack of bonafide Premier League nous is glaringly obvious and was an area which was not addressed in the summer window. It was ruthlessly exposed by Newcastle.
Anel Ahmedhodzic presented a case for being the best defender in the Championship last term. But the top flight is several levels up and a far different story as he is finding out.
United's main defensive acquisition in Auston Trusty remained an unused substitute on Sunday and in many ways that was a sensible move from Heckingbottom.
With his side imploding before his very eyes in brutal fashion, why subject a recent signing - with no Premier League experience - to punishment on a very bad day and potentially harm his confidence in the process?
Especially with him being an option in an area of the pitch where United's options are pretty thin in truth.
It is easy to see already as to what United's transfer priority will be in January.
To give himself a chance of getting that far, Heckingbottom must avoid another beating like Sunday in the not too distant.