Dominik Szoboszlai and Alexis Mac Allister were on target either side of half-time as the Reds further stretched their advantage after Arsenal were earlier held 0-0 at Nottingham Forest. Unbeaten in 24 league games, Liverpool are cruising towards a record-equalling 20th English top-flight title but just their second in 35 years. Defeat leaves Newcastle down in sixth, three points adrift of the top four.
Liverpool boss Arne Slot had to make do with a seat in the stands after being handed a two-match touchline ban for his red card in a fiery Merseyside derby at Everton earlier this month.
With Slot's assistant Sipke Hulshoff also banned, it was another member of his coaching staff - former Everton defender - Johnny Heitinga who patrolled the touchline.
The sides will meet again in the League Cup final on March 16.