They remain two points behind Liverpool and Chelsea, who both have 100% records after four matches, but it needed a bolt from the blue to do so.

Despite Walker's prowess as a marauding full-back his last goal came in November 2015 so to see him rifle home a 25-yard winner early in the second half was something of a surprise.

Raheem Sterling's eighth-minute opener on his 100th Premier League appearance for the club was cancelled out by DeAndre Yedlin - another defender not known for his aptitude in front of goal.

With Newcastle, yet to win this season, set up to contain and hoping to avoid the sort of 6-1 hammering Huddersfield got here a fortnight ago, City had the freedom of the Etihad.

The first half resembled an attack-versus-defence training-ground exercise as the visitors regularly ceded possession to invite yet another blue wave to crash over them.

A first Premier League start for Riyad Mahrez saw the £60million summer signing drag wide an early chance but the breakthrough was not long in coming.

If Newcastle's captain Jamaal Lascelles, restored to the starting line-up after injury, was looking to redeem himself after a reported training ground bust-up with Matt Ritchie, he failed miserably.

A horrible miscontrol saw him gift possession to Benjamin Mendy, who released Sterling outside him and the England international cut in from the left to curl a shot across Martin Dubravka and inside the far post.

That is usually the signal for the floodgates to open, but for all their control the hosts unusually lacked a cutting edge.

Sergio Aguero, who had previously scored 14 in 11 appearances against Newcastle, whipped an effort wide from distance while Gabriel Jesus shot straight at Dubravka.

But while City, who omitted winger Leroy Sane from their matchday squad, were contemplating how to open up the visitors' five-man defence again, they were caught napping on the half-hour.

Kenedy played in Salomon Rondon on the left and he slid a low cross into the six-yard box towards the far post where Mendy would normally have expected to have been guarding.

However, the France international had been dragged into the middle and Yedlin capitalised on the wide open space in front of him to charge forward from the halfway line, past the back-tracking Jesus, and convert from close range.

City came out a different side after the break and within eight minutes were ahead again as Newcastle again failed to learn from allowing Sterling to cut in from the left, the England forward offloading for Aguero to tee up Walker to drill home.

That goal appeared to break Newcastle's resolve as Jesus was denied by an offside flag before Dubravka made a good double save from Fernandinho and David Silva, who also missed a far-post header as City belatedly clicked into gear.

The result leaves Newcastle with just one point - a draw against newly promoted Cardiff - and manager Rafael Benitez, after their midweek Carabao Cup exit to Nottingham Forest, with more questions to answer.

It does not get any easier for the Spaniard as Arsenal are next up, the third member of the Big Six they have faced already this season.