Strap yourself in. It looks like it's going to be a little hairy from here. For all their energy going forward Liverpool have begun to creak in the same places they were so brutally crisp and decisive for the first half of the season. It's a cliche because it's true, or true enough anyway: a top-class attack might get you to the Champions League final; an unforgiving defence wins league titles. And something has shifted here for Jürgen Klopp's team.
Since St Stephen's Day, and including this slightly angsty evening at the London Stadium, Liverpool have kept one clean sheet in seven games. This is hardly a surprise. Three key players are missing from the defence: the superb Joe Gomez, the impressive Trent Alexander-Arnold and the actually-not-bad Dejan Lovren.
Joël Matip started here and had a tricky night. Elsewhere James Milner’s ankle-chomping authority was missed in midfield as he filled in at right back. Naby Keïta continues to look like the incomplete central midfielder.
More to the point there were periods where the league leaders made West Ham look like a team of attacking terrors. The same West Ham who had scored one league goal in three games before last night had seven shots at goal in the first half alone. At times they looked viciously effective on the break, with Felipe Anderson parading his lovely, easy range of skills on the left. Ten minutes into the second half Anderson dropped deep and turned away from Matip like a man absent-mindedly swerving a discarded traffic cone. Matip pulled him back and was booked. Right now this is not a defence to ease your way gently into a title run-in.
Klopp knows it better than anyone, of course. Before last night Liverpool’s manager had promised his team would simply attack from here, press the pedal, look to go forward without breaking a step in all competitions. They might just have to because right now Liverpool are not in the shape to win it clean. It is going to be a little messy, a little raw, from here. And perhaps that tension is starting to bite just a little.
Klopp's response to the draw with Leicester was to open up his team, bringing in Adam Lallana to start in midfield for the first time since October, a player who is all soft touch and clever movement, with the ability to spin and divert the ball at high speed with a nudge of the rudder. He is a strange, likeable sui generis footballer, his actual "goal involvements" no real reflection on his craft, his poise on the ball.
Finding another way to win, another way to score can be vital at moments like these and Lallana may well have a hand to play, as he did in Liverpool taking the lead on 22 minutes. It must have felt sweet. All the more so, perhaps, as it involved a huge stroke of good fortune for an unlucky footballer. Lallana took the ball way out on the right touchline, with his back to goal and two defenders close. He swayed and rolled the ball around with his toe, then back-heeled a ball between two defenders into James Milner’s run.
Milner was miles offside. He didn't hesitated. His low cross was finished neatly by Sadio Mané. The game could have gone one way from there, but West Ham had come here to play. The sense of injustice was soothed almost instantly as Michail Antonio ran away from the wall at free-kick, took a cute slid pass and spanked the ball hard and low into the corner. Keïta had simply watched him go. It was an embarrassing goal to concede.
On his touchline Manuel Pellegrini stood and barely flinched, features betraying just a glint of some ancient weathered joy. And as the second half wore on West Ham continued to pull that defence out of shape in between the Liverpool attacks, to press at some tender points that have opened only as the season enters its final straight.