Key battles

Roberto Firmino v Chris Smalling

A false nine like Firmino gives old-fashioned centre-backs like Chris Smalling a problem. At times, he will have no one to mark. Yet the Brazilian represents a dangerous opponent. He has scored only three goals for Liverpool but one came against Manchester City and two against Arsenal. He should be confident after Wednesday's brace.

Alberto Moreno v Anthony Martial

Martial has taken some persuading that he can play on the right. Yet with Juan Mata's lack of pace counting against him, the Frenchman has been switched. He presents a test for Moreno, who has excelled going forward under Juergen Klopp and would rather attack makeshift right-back Ashley Young, but has defensive deficiencies.

Mamadou Sakho v Wayne Rooney

Rooney is savouring the new year. The scorer of just six Premier League goals in 2015 has three already in 2016. Restored to the striker's role, he has regained his knack of scoring spectacular goals and is fighting to keep Louis van Gaal in the job. Sakho is Liverpool's best centre-back, but colleague Kolo Toure could be a weak link.