Sergio Aguero was unlucky in the sixth minute to see his outstretched strike at far post hit the frame of the post following a looping cross from Fernandinho.
Man City captain and defender Vincent Kompany was unfortunate to be forced to leave the field because of injury and was replaced by striker Gabriel Jesus.
Kevin De Bruyne could have opened the scoring in the 21st minute with a point-blank range header, but he was denied by the brilliance of Rob Elliot between the sticks.
However, City found the breakthrough in the 31st minute after an inviting chip into the box by De Bruyne found Raheem Sterling, who turned the ball home with a left-footed finish.
Jamaal Lascelles almost equalised four minutes later with a goal-bound header at close range, but his effort could not find the target.
Guardiola's charges were dominant in the closing stages of the half and threatened to extend the lead but Newcastle were lucky to head into the break trailing by the one goal.
Seven minutes after the break. Sterling produced great footwork to beat two markers on the edge of the box and bent a right-footed strike that sailed slightly wide.
IIkay Gundogan could have extended Man City's lead four minutes before the hour mark with a curling low strike, but Elliot did well to save at full-stretch.
Rafa Benitez made his first change on the hour-mark by bringing on Dwight Gayle in place of Joselu while he also brought in Christian Atsu 10 minutes later in place of Roland Aarons.
Gayle was sent through on goal in a rare chance for the Magpies 15 minutes before time but while going clear on goal inside the box he opted to dive under pressure from Danilo and was booked for simulation.
Gayle nearly equalised with two minutes left on the clock with a diving header from Atsu's cross inside the six-yard box but his effort went wide.
United pressurised City in the closing stages of the half, but it was not to be as Guardiola's troops held on to claim their 18th consecutive league win.