The £125m summer signing had endured a frustrating start to life at Anfield, managing only one Carabao Cup goal in 10 league appearances before arriving at the London Stadium. But on the hour mark the Swedish striker produced the moment Slot has been waiting for, sweeping Cody Gakpo’s low cross into the bottom corner to put the visitors ahead.

Gakpo added a second late on after bringing down Joe Gomez’s lofted pass on his chest before rifling past Alphonse Areola, sealing Liverpool’s first league win in three matches.

The match began under a sombre cloud after the death of West Ham legend Billy Bonds, whose passing was confirmed just hours before kick-off. Jarrod Bowen placed a claret-and-blue No.4 shirt in front of the home end as supporters delivered a minute’s applause for the former captain and manager.

Once the game settled, Liverpool took control. Isak saw two chances go begging in the first half one skied from the edge of the box, another beaten away by Areola but his movement continued to trouble a West Ham side lacking imagination in the final third.

There was a surprise before kick-off when Mohamed Salah was omitted from Slot’s starting XI. The Egyptian’s modest return of five goals in 18 appearances has prompted questions about his role under the new manager, and even when Isak was withdrawn shortly after scoring, Slot opted to introduce Hugo Ekitike instead of his long-time talisman.

Salah eventually entered the fray with the game already tilting Liverpool’s way, but the message from Slot felt deliberate.

If West Ham had any hope of rescuing something late on, Lucas Paquetá ended it. The Brazilian, only just back from suspension, talked himself into a red card with six minutes remaining after reacting angrily to a routine free-kick awarded to Liverpool. His continuing protests forced the referee to upgrade the initial yellow to a dismissal, leaving Nuno Espírito Santo furious on the touchline.

West Ham’s sterile display did little to ease relegation concerns. They remain just above the bottom three on goal difference and produced almost nothing to trouble Alisson, whose quiet afternoon summed up a blunt attacking effort.

For Slot, this was a much-needed afternoon of calm after a fortnight dominated by speculation over his future. Liverpool climbs to within a point of the Champions League places and now faces Sunderland and Leeds fixtures that offer a chance to inject momentum into a stuttering campaign.

As for Isak, his celebration told its own story. After weeks of scrutiny and hesitation in front of goal, Liverpool will hope this breakthrough finally sparks the striker they believed they were signing.