The intense spotlight that has been trained on one elite Liverpool great shifted to another on Anfield's most recent disappointing night.
Mohamed Salah has faced examination for his struggles this campaign - and was relegated to the sidelines for the second successive Premier League game as the Black Cats came to town on Wednesday.
But it was captain Virgil van Dijk, a peerless defensive rock as Liverpool have secured the full collection of major trophies, whose poor form took center stage during the 1-1 draw.
Van Dijk, 34, and Salah, 33, both agreed to lucrative new two-year deals in the summer, with scarcely a Liverpool concern voiced at the idea of offering extensions to a experienced stars much approaching the end of their careers than the start.
Truly, it was a reason for joy - but now there is no avoiding the harsh truth that levels have fallen worryingly for both.
Liverpool have been vulnerable in defence ever since boss Arne Slot and the club's transfer committee undertook a £450m summer overhaul that has yet to prove anything like its worth.
At the same time, Van Dijk has started to shed the sense of being untouchable he has possessed since his £75m switch from Southampton in January 2018.
Van Dijk has not been helped by center-back colleague Ibrahima Konate's loss of form, along with Milos Kerkez struggling to adapt at left-back. But the renowned star has also had significant difficulties, as proved by his panic-stricken handball that resulted in a penalty in the heavy Champions League loss to PSV Eindhoven at Anfield.
It was exemplified in the 67th minute on Wednesday when Chemsdine Talbi gave Sunderland a merited lead, Van Dijk giving the ball away before standing off and turning away on a 25-yard shot that struck him and floated out of the reach of goalkeeper Alisson.
For a defender of such unquestionable quality, Van Dijk has an peculiar tendency of turning away on the ball, sometimes to Liverpool's detriment.
Bad luck at the finale, yes, but it was a situation Van Dijk provoked with his unusual failure to take charge, Sunderland's Talbi capitalising.
"Van Dijk gives the ball away and then he just drops off. It's the mistake. He needs to go to the ball. Him not making the decision means that no one else knows what to do."
"Virgil Van Dijk last season was impeccable. Every game he was dominant, but right now he's erring and hesitating."
As with Salah, a player of Van Dijk's caliber must not be discarded after winning two Premier Leagues, the Champions League, the FA Cup and two EFL Cups in a illustrious Liverpool career.
He has, though, looked a pale imitation of his usual imperious self this season, with the lowest recovery numbers per game during his Liverpool career, while key defensive stats are also down on last season.
And, while leadership should not be Van Dijk's preserve alone in a Liverpool team brimming with experience, it was absent here. No-one was inspiring a team that once again looked bewildered to seize the initiative by the initiative.
Van Dijk's difficult night, which ended with him being used as the emergency option of acting as an makeshift forward, was representative of a distinctly poor Liverpool performance - which made Sunday's win at West Ham seem like the anomaly rather than the rule.
Slot stayed with the side that stopped a run of nine losses in 12 games at London Stadium, Salah once more starting on the sidelines.
The Egyptian was introduced at the start of the second half as the Kop pinned hopes on him for inspiration. It was not forthcoming, with £125m Alexander Isak also quiet after opening his account with his first league goal for Liverpool on Sunday.
Slot would have been under increased scrutiny had Florian Wirtz's 81st-minute shot not taken a deflection off Nordi Mukiele to set up what Liverpool hoped would be a dramatic ending.
Late drama came - but at the other end. Liverpool were only avoided defeat in stoppage time when Federico Chiesa's superb tracking back allowed him to turn Sunderland substitute Wilson Isidor's shot off the line after he had beaten keeper Alisson.
Slot and his underperforming defending champions ultimately had to settle for a draw knowing it could have been worse, with Alisson fortunate to turn Trai Hume's shot onto the bar in the first half before Omar Alderete headed against the post after the interval.
Liverpool were sluggish, ponderous and short on invention. Even the customary late surge after the equaliser carried scant belief. Displays like this are the reason their title defence has collapsed.
But huge credit for the Reds' struggles on Wednesday must be given to Sunderland, who are being seeing the results for a summer of notable ambition in the transfer market, coupled with the superb management of Regis le Bris.
The Black Cats were adventurous, self-believing and a genuine threat.
Sunderland are now sixth in the Premier League with 23 points. It is telling of the manner in which they have grown into life in the Premier League that they will be unhappy they left Anfield without adding two more to their tally.
For Slot and Liverpool, it is time for reflection.
A tech journalist and VR specialist with over a decade of experience covering emerging technologies and digital culture.