An astonishing first-half performance has given Albion an almost unassailable 4-0 lead.
Deniz Undav opened the scoring with his first Premier League goal and it survived a VAR check for offside. Danny Welbeck was the provider.
Pascal Gross grabbed two – the second of which was a superb dipping volley. Julio Enciso set up Gross for both goals.
Then a header from Welbeck set an Albion record for their most goals in a top-flight match.
Joel Veltman picked up a yellow card just before the end of six minutes of added time.
