Roberto Firmino is Liverpool's most important player as he "makes everything tick" for Jurgen Klopp's side, according to former striker Emile Heskey.
Firmino came off the bench to help the Reds beat Newcastle United 3-1 on Saturday and extend their run to 14 consecutive victories in the Premier League.
Liverpool were level when Firmino replaced the injured Divock Origi, with Sadio Mane having cancelled out Jetro Willems' opener, but the Brazil international helped set up Mane's second within three minutes of his introduction.
A sublime backheel to Mohamed Salah led to the home side's third at Anfield, which secured a result that puts them five points clear of champions Manchester City after five matches.
Heskey, who spent four years on Merseyside and was often used as a link between midfield and strike partner Michael Owen, believes Firmino turns Liverpool into a stronger side as he makes life easier for his attacking team-mates.
"I would say Firmino [is most important] and the reason I say that is he's the one that makes everything tick when it comes to the front three," Heskey told Omnisport.
"Take him out of there, yes, they will get you goals, yes, they will cause havoc but they won't do it in the same fashion that they do with him.
"He makes everything tick, everything goes through him and it just looks smoother when it goes through him, and they create more chances when he's in the team."
While Firmino's selflessness is an asset to Liverpool, Heskey believes Manchester United striker Marcus Rashford would benefit from being more single-minded.
Rashford's penalty gave United a 1-0 win over Leicester City on Saturday and took his tally to three goals in five league games this term, but Heskey thinks the England forward's versatility is perhaps holding him back from becoming a more ruthless finisher.
"I would like to think Marcus Rashford's best position is centre-forward," Heskey said. "But as you say, he can play all along the front line because he's got that ability. He's very direct, he's very quick, he's got a skill in him, and he doesn't mind providing.
"Now, if you're a centre-forward that wants to score goals, and goals only, you don't want to be pushed on the left or the right because you know you're not going to score from there. You want to be right in the middle where you can score goals. He's more of an unselfish player that you could actually play in different positions."