#1 Virgil Van Dijk (Liverpool)
It is really simple, without Van Dijk at the back, Liverpool would not be top of the league. It is difficult to overstate the sea-change in the Reds backline since the Dutchman arrived from Southampton in January 2018.
He has brought calm, organization and intelligence to a defence that was leaking goals for fun before. With him as the leader, the backline has become the team's biggest strength and the main reason why fans are dreaming of a first ever Premier League title.
Calm, unhurried, brilliant aerially with a great sense of timing, the captain of the Oranje has been perhaps the most important signing of the Jurgen Klopp era (even above Mohamed Salah).
With him orchestrating, the Reds now have the strongest defence in the league. They have let in just 8 goals conceded in 20 matches. That is half of what Manchester City has conceded (16)
He has in his first full season as a Liverpool player shown why a world-record fee (for a defender) of £75m was paid for his services.