Liverpool's Roberto Firmino celebrates scoring their fifth goal to complete his hat-trick during the match Premier League between Watford vs Liverpool at Vicarage Road, Watford, October 16, 2021. Mohamed Salah set up Sadio Mane's 100th Premier League goal and scored a brilliant goal of his own, while Roberto Firmino bagged a hat-trick as Liverpool reclaimed top spot with a 5-0 win over Watford. Action Images via Reuters/Andrew Couldridge

Liverpool's Roberto Firmino scores their fifth goal to complete his hat-trick during the match Premier League between Watford vs Liverpool at Vicarage Road, Watford, October 16, 2021. Action Images via Reuters/Andrew Couldridge

Liverpool's Roberto Firmino scores their first goal during the match Premier League between Watford vs Liverpool at Vicarage Road, Watford, October 16, 2021. Action Images via Reuters/Andrew Couldridge

Liverpool's Roberto Firmino celebrates scoring their fifth goal with Virgil van Dijk during the match Premier League between Watford vs Liverpool at Vicarage Road, Watford, October 16, 2021. Action Images via Reuters/David Klein

Liverpool's Sadio Mane scores their first goal during the match Premier League between Watford vs Liverpool at Vicarage Road, Watford, October 16, 2021. REUTERS/David Klein

Liverpool's Mohamed Salah in action with Watford's Ben Foster during the match Premier League between Watford vs Liverpool at Vicarage Road, Watford, October 16, 2021. Action Images via Reuters/Andrew Couldridge