Liverpool were guilty of complacency against West Brom, according to Stephen Warnock, who says the Reds "stepped off the gas".
Jurgen Klopp's side missed the chance to open a five-point lead at the top of the Premier League table after being held to a 1-1 draw by struggling West Brom on Sunday.
Liverpool took the lead after just 12 minutes at Anfield, with Sadio Mane volleying home after controlling a powerful pass from Joel Matip.
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Reds supporters would have expected the floodgates to open after that goal, having seen the Reds dismantle Crystal Palace 7-0 in their previous fixture, but the Baggies defended well to stay in the match.