The unforgiving attention that has been trained on one world-class Liverpool legend turned to another on Anfield's fresh disappointing night.
Mohamed Salah has been under scrutiny for his subpar performances this campaign - and was relegated to the bench for the consecutive Premier League game as the Black Cats arrived on Wednesday.
But it was skipper Virgil van Dijk, a peerless defensive rock as Liverpool have secured the array of major prizes, whose struggles took center stage during the stalemate.
Van Dijk, 34, and Salah, 33, both signed high-value two-year deals in the summer, with scarcely a Liverpool eyebrow raised at the idea of securing the futures to a veteran duo much closer to the end of their careers than the start.
Indeed, it was a moment of optimism - but now there is no escaping the harsh truth that standards have dropped concerningly for both.
Liverpool have been susceptible in defence ever since manager Arne Slot and the club's recruitment team undertook a £450m summer refit that has still to demonstrate anything like its worth.
At the same time, Van Dijk has started to forfeit the air of invincibility he has possessed since his £75m move from Southampton in January 2018.
Van Dijk has received little support by center-back colleague Ibrahima Konate's collapse in form, along with Milos Kerkez struggling to adapt at left-back. But the great Dutchman has also fought his own battles, as highlighted by his rash handball that conceded a penalty in the heavy Champions League loss to PSV Eindhoven at Anfield.
It was captured in the 67th minute on Wednesday when Chemsdine Talbi gave Sunderland a merited lead, Van Dijk losing possession before backing away and averting his body on a 25-yard shot that hit him and looped out of the reach of goalkeeper Alisson.
For a defender of such unquestionable quality, Van Dijk has an peculiar tendency of turning his back on the ball, sometimes to Liverpool's disadvantage.
Bad luck at the end, yes, but it was a situation Van Dijk invited with his atypical failure to make a decisive move, Sunderland's Talbi seizing the moment.
"Van Dijk surrenders possession and then he just backs off. It's the incorrect choice. 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 imperious, but right now he's slipping up and hesitating."
As with Salah, a player of Van Dijk's caliber must not be dismissed after claiming two Premier Leagues, the Champions League, the FA Cup and two EFL Cups in a illustrious Liverpool career.
He has, though, looked a shadow of his usual dominant persona this season, with the lowest recovery numbers per game during his Liverpool career, while defensive actions are also down on last season.
And, while leadership should not be Van Dijk's preserve alone in a Liverpool team packed with experience, it was missing here. No-one was inspiring a team that once again looked clueless to seize the initiative by the initiative.
Van Dijk's poor display, which ended with him being used as the desperate measure of acting as an makeshift forward, was representative of a deeply underwhelming Liverpool performance - which made Sunday's win at West Ham seem like the outlier rather than the standard.
Slot persisted 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 emerged at the start of the second half as the Kop turned to him for inspiration. It failed to materialize, with £125m Alexander Isak also quiet after getting off the mark with his first league goal for Liverpool on Sunday.
Slot would have been under greater pressure had Florian Wirtz's 81st-minute shot not taken a deflection off Nordi Mukiele to set up what Liverpool hoped would be a grandstand finish.
Stoppage-time tension came - but at the other end. Liverpool were only saved from humiliation in stoppage time when Federico Chiesa's outstanding recovery run allowed him to turn Sunderland substitute Wilson Isidor's shot off the line after he had rounded 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, labored and short on invention. Even the customary late surge after the equaliser carried minimal threat. Performances like this are the reason their attempt to retain the title has crumbled.
But significant praise for the Reds' struggles on Wednesday must be given to Sunderland, who are being reaping the benefits for a summer of notable ambition in the transfer market, coupled with the excellent coaching of Regis le Bris.
The Black Cats were positive, self-believing and threatening.
Sunderland are now sixth in the Premier League with 23 points. It is symptomatic of the manner in which they have adapted to life in the Premier League that they will be disappointed they left Anfield without adding two more to their tally.
For Slot and Liverpool, it is time for reflection.
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