Liverpool's problems mounted as Manchester United condemned them to a fourth consecutive defeat for the first time since 2014. They are not the only Premier League club in crisis right now.

Nottingham Forest have gone from a Champions League fight to a relegation battle, with Sean Dyche set to become their third head coach in a turbulent season following Ange Postecoglou's sacking.

Wolves are winless after eight games at the bottom of the table and there are issues at West Ham too, with fans staging protests as Nuno Espirito Santo fights to turn their season around.

This week in Between the Lines, the new Sky Sports strand unpicking the data behind the biggest stories in football, we pull out the key issues behind each club's struggles this season.

Liverpool: Salah, Wirtz woe and defensive dip

When does a loss of form become a decline? Mohamed Salah's struggles put him near the top of Liverpool's list of problems.

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Jamie Carragher gives his verdict on Mohamed Salah's decline

Salah produced one of the great individual Premier League campaigns...