Liverpool took the lead in the fifth minute through Roberto Firmino who chipped Ben Forster after Mohamed Salah’s initial effort was saved.
West Brom were back on level terms thanks to Jay Rodriguez in the seventh minute who fired on from the edge of the area to make it 1-1.
In the 11th minute, West Brom went 2-1 up through Rodriguez again after stroking home Kieran Gibbs’ pass.
West Brom thought they had extended their lead after Craig Dawson headed in from a corner but the goal was chalked off for offside after consultation with the Video Assistant Referee (VAR).
At the other end, Liverpool were awarded a penalty following the use of the VAR again following Jake Livermore’s foul on Salah but Firmino’s strike came off the bar.
Two minutes into added time, West Brom got their third goal as Joel Matip turned in Dawson strike to make it 3-1.
For the third time in the game, the VAR was used but this time the decision went in West Brom’s way as the goal was given.
And with 12 minutes left Salah made it 3-2 as he slammed the ball past Forster after the West Brom defence failed to properly clear a cross.