Wirtz has struggled to find his best form for the Reds following his big-money transfer this summer. The 22-year-old has still shown promise in spells but has not provided enough to The Reds to justify his price tag as of yet.
Despite setting up Hugo Ekitike for the first goal in the Community Shield match against Crystal Palace over two months ago, the German international has failed to score or assist since then.
Speaking to GOAL, Murphy has backed Wirtz and handed him a target which is more than possible for the young midfielder who grabbed 16 goals and 14 assists for Leverkusen last season.
"It’s a difficult one because I think if Liverpool win the Champions League or win the league, his numbers become less relevant and the microscope on them becomes less because there has been collective success.
"If he is going to play the majority of the season as a 10 then you have got to be looking at, ideally, double figures for assists and goals - that would be a success. I think he has been a tad unfortunate in some ways, although you have to accept that he hasn’t started as well as we anticipated.
"I think he has been a bit unlucky because he has made a lot of chances that haven’t been converted. Sometimes if some of those go your way - (Mohamed) Salah missed a sitter against Everton, (Jeremie) Frimpong missed a sitter, a couple at Galatasaray, the beautiful flick at Chelsea that Salah mis-hit on his right foot.
“All of a sudden the narrative changes a little bit if a few of those go in, or it’s not as intense.”
The 22-year-old is under increasing scrutiny and as Liverpool face off against Manchester United this weekend, he has the perfect chance to get on the scoresheet and build up momentum and shrug off his critics.