If Simon Grayson had been relatively relaxed after the Leeds United defeat, this one left him bristling with anger.
He had been utterly irate for the final 20 minutes, barking at his defence to get up the field, barking at Wahbi Khazri when the substitute lost the ball in a dreadful area of the field.
His post-match remarks about hunger and complacency were delivered in an even more urgent tone than after the abject pre-season defeats to St Johnstone and Celtic.
This one stung.
Barnsley’s win was the kind Grayson has been used to chasing with Preston.
The former Premier League team – buffered by parachute payments, superior technical quality and a massive wage bill – out-thought and outfought by his well organised side.
His admiration for a Barnsley side that has been picked apart by the vultures in recent months and rebuilt, full of desire and with a clear team ethic, was obvious. They looked the kind of team he has always tried to build, wherever his career has taken him.
We saw in 90 minutes at Oakwell the challenge that will define his Stadium of Light tenure.
He has managed a club of this size before, a successful stint at Leeds United, but there he picked them up in League One and built a squad of up-and-coming players.
Here, he has picked up a Sunderland squad reeling from a torrid season, where the divides are obvious and where some players want out.
Many who do not have had their confidence eroded by the Premier League struggles.
To motivate, organise and improve will serious take man-management skill.
It also takes him out of his comfort zone, having previously been able to work with players like those at Barnsley, those desperately trying to make their way in the game, fighting for their careers.
There have been some encouraging signs. For all they floundered at Oakwell, Tyias Browning, Aiden McGeady and Lewis Grabban have shown some positive signs, while it is too soon to write off Robbin Ruiter despite a disappointing league debut.
He needs help.
It is no secret that the Black Cats boss would like to move on the likes of Wahbi Khazri, and, despite his occasionally excellent showings this season, he would not mourn the loss of Lamine Kone, either.
He is ready to move for replacements and the profile of those players will follow those who have already arrived on Wearside.
The quality of the squad may therefore dip, but Grayson will happily make that sacrifice if it means he can build a team where he can trust every player to follow his tactical instructions, particularly off the ball, where Sunderland were a mess on Saturday afternoon.
He needs chief executive Martin Bain to help make it happen. If investment does not materialise fans will quite rightly ask why given the squad’s shortcomings.
It was impossible not to be impressed with the obvious pride in the Barnsley ranks, the talented young side that has emerged from humble surroundings and from a budget that ought not to be competitive.
They quite rightly claimed the scalp of a side that boasted superior talent but didn’t match their application.
That will have wounded Grayson, who is not used to being on the receiving end of that kind of defeat.
Instilling Barnsley’s hunger has come easily for him at oher clubs, but is another challenge altogether here.
This was a chastening reality check.