Is Newcastle v Liverpool the Premier League’s new toxic rivalry?

The cause of this friction, Liverpool’s interest in Isak, will continue to the end of the transfer window and probably beyond.

Newcastle’s supporters were in no mood to forgive or forget how their star striker has, in their eyes, betrayed them, and the club they hold responsible as the catalyst for his desire to leave.

This is now shaping up as a conflict for the ages, especially as it is unclear how the story that has caused the antagonism will end.

Liverpool’s fans revelled in how their interest in Isak has caused such rage among the Toon Army, their chants of “Hand Him Over Newcastle” greeted with a frenzy of indignation.

Newcastle need a resolution somehow, even if fences look almost impossible to repair with Isak. They cannot allow him to be the spectre hanging over every game.

Liverpool won this particular battle, but the other big takeaway on this evidence is they need to focus their attention on signing a defender, presumably Crystal Palace’s Marc Guehi, before making any definitive decision on Isak.

As against Bournemouth in their first game of the season at Anfield, Liverpool let slip a 2-0 lead before winning late on, looking horribly vulnerable in defence in the process.

The advantage they forged for themselves here flattered them as they piled up mistakes at the back and carelessly conceded possession with regularity.

And Slot should be seriously concerned about how they were shaken up so badly by Newcastle’s 10 men. Indeed, before Ngumoha’s strike, it was Newcastle who looked more likely to score.

Liverpool, in only two games admittedly, have looked nothing like the side that strolled to the Premier League last season with such poise and assurity, apart from the fact they are still winning games.

Ibrahima Konate, the player most at risk from Guehi’s potential arrival and who has yet to agree a new contract, was as uncertain as he was against Bournemouth. Slot also has yet to find the tweak to ensure he brings the best out of £116m attacker Florian Wirtz, who was substituted with 10 minutes left.

Left-back Milos Kerkez is still settling in, but the chaotic nature of Liverpool’s backline could have Slot pondering the return of the experienced Andrew Robertson, who has the proven quality and greater understanding with his defensive colleagues.

Newcastle will be nursing their wounds over this loss as they try to find a way to end the Isak impasse.

This rivalry, like the discussions around Isak’s future, is one that will run and run.