Liverpool have given their hopes of a top four finish a boost with a hard-fought 1-0 win over West Brom.
The Brazil striker headed in at the end of the first half after Lucas Leiva had glanced on James Milner's free-kick.
They are unbeaten since losing at Leicester in late February and now lead fourth-placed Manchester City by two points, although Pep Guardiola's team have a game in hand in the race for an automatic spot in the Champions League group stage.
Chelsea now leads the EPL with 75 points, with a four-point difference ahead of second-placed Tottenham Hotspurs.
West Brom midfielder Claudio Yacob carelessly coughed up possession inside his own half in the 15th minute, allowing Philippe Coutinho to scamper towards goal and play in Firmino, who dragged wide left footed.
Pulis' men would go no closer to getting on terms - the Arsenal win before last month's global break standing as the only game in the last seven where they have found the net.
Tony Pulis' men continued to make life hard for their opponents with Nacer Chadli missing a glorious chance at the far post.
Instead he missed his kick and Liverpool nearly broke away and scored.
Milner skewed a great chance to double Liverpool's lead when Firmino picked him out at the far post in the second half, only for the former England global to fire over the bar.More news: Bahrain Grand Prix: Hamilton takes blame for penalty
"He's a good boy, really".
Gary Lineker expressed his surprise that West Brom conceded from a free-kick after Roberto Firmino scored Liverpool's victor in a 1-0 victory at The Hawthorns.
"In the second half we did much better, but we kept the ball in the first half and didn't let them be really part of the game".
Milner should have scored moments later when he arrived late to meet a cross by Firmino, only to side-foot a volley over the crossbar.
West Brom's dour form in front of goal meant Liverpool were scarcely tested until 10 minutes from time.
Substitute Salomon Rondon played Matt Phillips through, only for goalkeeper Simon Mignolet to spread himself and block the winger's attempted chip.
The winger connected well with his shot but it was smothered low down by Mignolet.
Deep into injury time, substitute Alberto Moreno spurned a simple chance to score from 35 yards out after Ben Foster was caught upfield from a corner, but the Spaniard could only hit his shot wide.