West Brom created the best chances in a largely uneventful first half before Firmino nodded home Lucas’ flick on to register his 11th league goal of the season just before the break.
The visitors could have extended their lead after halftime, but James Milner blazed a glorious opportunity over the bar and Divock Origi had a goal ruled out for offside.
Simon Mignolet made a crucial late save to deny Matt Phillips but, as West Brom piled on the pressure in the closing stages, Alberto Moreno missed an open goal after Ben Foster had come up for a corner.
Liverpool have 66 points from 33 games, although they have played one more game than
“If you come away to
“We are very pleased with the performance, and the three points is massive today. You feel the pressure after you see the other teams and their results, but we have to look at ourselves and do our jobs.”
The hosts, however, had failed to score in their previous three league fixtures, but carved out a couple of promising chances through Hal Robson-Kanu and Nacer Chadli.
A goalless halftime beckoned at the end of a cagey first half before Firmino rushed in at the back post to convert Lucas’ flick-on past goalkeeper Foster.