The league leaders were gifted a fifth-minute opener as Newcastle defender Ciaran Clark failed to attack Joao Cancelo’s hooked cross and Ruben Dias had a simple task to head City ahead.
City doubled their lead in the 27th minute when Cancelo collected the ball 35 yards out, beat two Newcastle players and fired an unstoppable strike into the top corner from outside the penalty area.
Riyad Mahrez scored his 50th Premier League goal for the club in the 63rd minute, superbly volleying in Oleksandr Zinchenko’s cross for City’s third.
It got even worse for the hosts as Raheem Sterling tapped in from close range four minutes from time after a fine run down the left flank from Gabriel Jesus.
This victory ensures City will be top of the Premier League at Christmas for only the third time – and on both previous occasions in 2011-12 and 2017-18 they went on to be champions.
Newcastle remain 19th in the table, three points behind 17th-placed Watford and with only goal difference keeping them above bottom club Norwich City.