For a brief period of the second half, despite all the possession and most of the chances, Liverpool were behind - at home - in a league game.
But this is a different Liverpool Football Club. This is the Liverpool who have won 110 points from the last 114 available (38 games).
A team that is unbeaten in 44 league games and has erected 20 foot walls and a moat around Fortress Anfield.
With almost 3 months of the season to go, the reds could theoretically lose every single game, and the worst they would finish would be 3rd.
Sadio Mane stepped up for the winning goal towards the end of the game, to restore Liverpool's mammoth 22 point lead at the top of the division.
West Ham arrived fighting for their Premier League survival, Liverpool barely need to move forward to claim a 19th title, but still found the energy and reserves and focus to overturn a potential 2-1 defeat.
Liverpool even had time for a fourth goal to be ruled out by that supposed friend of the reds - VAR.
The scoreline reads a one goal margin, but the reds were by far the better team on the night. The reds strikers wasted a host of chances, shots over the bar, headers over the bar, shots diverted wide by arms in the area, crossbars.
At the other end, Alisson was beaten twice - a rare experience for him and perhaps he could have done better for the first Hammers goal.
Klopp had drafted in Naby Keita to replace Henderson, and he had a not-great/not-awful game. The arrival of Alex Oxlade-Chamberlain to replace him coincided with Liverpool going behind, and Anfield finally woke up from their opening hour slumber.
The night had started well with Trent Alexander-Arnold crossing for Gini Wijnaldum to head in after 9 minutes. The scouse right back was a constant menace all night.
But 3 minutes later it was 1-1. Liverpool undone by a corner sent into the near post. Alisson was distracted and failed to reach the header into the bottom corner of the net.
West Ham take the lead
Despite plenty of opportunities the score remained level at the break and it was West Ham, who against the run of play, took the lead in the second half. Declan Rice finding substitute Fornals unmarked by the penalty spot, who somewhat fortunately mis-hit it past Alisson.
The goal sparked The Kop into voice and Liverpool into action.
Alex Oxlade-Chamberlain launching a chance forward within seconds of coming on.
Fightback
Fabianski had kept Liverpool at bay with a number of saves, but Salah's weak shot from the edge of the area dribbled through his legs and the machine was back up and running.
We all knew how this game was going to end.
It was Trent again who provided the cross that took the West Ham keeper out the equation and Sadio Mane poked in the winner.
In the closing minutes of the game there was an almost exact replica fourth goal, but replays showed Mane had that time strayed offside so it remained 3-2.
West Ham had a final flourish before the referee blew the whistle on another incredible result in this most incredible of domestic seasons.
Liverpool require a maximum of 12 points from the next 33 to be crowned Champions.