The hosts rarely suggested they could reach a first semi-final in 15 years with Andy Carroll, starting his maiden match of 2020, isolated for lengthy periods in attack. Substitute Dwight Gayle could have levelled against the run of play past the hour but somehow fired over, and he was punished just moments later when Raheem Sterling fired a low drive into the far corner.
The victory means City will meet Arsenal in the last four on the weekend of 18-19 July.
Pep Guardiola's men will now switch their attention back to their next league encounter at home to newly-crowned champions, Liverpool on Thursday. Newcastle visit Bournemouth on Wednesday.
City cruise and could yet clean up with the cups. So, no real cup drama or surprises as City sail through in composed style. It may have been more difficult in front of a packed St James' Park crowd, but that's academic now and Newcastle's 65-year wait for a domestic trophy will go on. Guardiola's side may have missed out on the title, but they could yet end up having a fantastic season. The Citizens remain in the hunt to retain the FA Cup and claim the trophy for a seventh time. That would complete a domestic cup double (adding to the Carabao Cup won back in March at the expense of Aston Villa). And it could get even better if City can triumph at the Champions League 'final eight' tournament in August. That's the trophy Pep was brought into win after all. There's some way to go to achieve that, but there's no doubting this team's quality when on song.
MAN OF THE MATCH
Kevin de Bruyne (Manchester City). The birthday boy was given the freedom of St James' Park to showcase his range of passing in the attacking third. He took his goal with steely-focus from the spot to set his side on the path to victory before being given the luxury of an early finish.
12' - MAN CITY CHANCE! City should be ahead. De Bruyne finds Silva, who lays it back for Mahrez with plenty of time and space, but the Algerian blazes over from the edge of the area.
23' - MAN CITY CHANCE! Darlow reacts smartly to keep out Sterling's flicked effort after the ball had deflected kindly for the City forward. Total dominance from City as de Bruyne sees a low drive hit a Newcastle man and fly wide.
37' - GOAL! Newcastle 0-1 Man City. De Bruyne steps up and sends Darlow the wrong way with a firm, low spot-kick. The penalty was awarded for a shove on Jesus.
67' - NEWCASTLE CHANCE! Wow, how did he miss that? Gayle almost makes an instant impact off the bench, but somehow contrives to blaze over the bar from close-range after great play from Saint-Maximin on the right side of the City area.
68' - GOAL! Newcastle 0-2 Man City. Sterling makes the home side pay for the miss with a fine run and shot from 20 yards.
De Bruyne has been directly involved in 30 goals in all competitions this season (12 goals, 18 assists), four more than any other Man City player.
De Bruyne is the first Manchester City player to score a goal on his birthday since Nolito vs Everton in October 2016.
Sterling's goal for Manchester City was his first from outside of the box since netting against Shakhtar Donetsk in the Champions League back in November 2018.
Phil Foden has had a hand in seven goals in just six FA Cup appearances for Manchester City, scoring four and assisting three.