Despite its efforts in capturing the UEFA Super Cup in midweek, the treble champions' 17th successive home triumph was well merited.
Newcastle's 5-1 hammering of Aston Villa last weekend boosted expectations on Tyneside that the Magpies may be the best of the rivals to City's English title.
On this evidence, Pep Guardiola's men will be hard to stop in their bid to become the first team in English history to win four successive Premier League titles.
Three days after his team's triumph against Sevilla in Athens on penalties, Guardiola was enraged that the Premier League had scheduled the game.
The absences of Bernardo Silva and John Stones have also strained City's roster early in the season, while Kevin De Bruyne will be sidelined for up to four months with a hamstring injury.
But hopes that the Magpies might challenge City for their first top-flight league title in 97 years were dashed by City's dominance as fatigue crept in late.
The visitors were delighted to give up possession before the break, but City needed a bit of magic to get through.
Alvarez might be one of the beneficiaries of De Bruyne's extended absence.
Despite playing second fiddle to Erling Haaland, the Argentine scored 17 goals in his first year at Manchester.
Guardiola may now be obliged to pair Alvarez with the Norwegian more frequently, and he demonstrated his abilities in 31 minutes with a spectacular goal into the top corner from Phil Foden's ball.
Young guns of City playing a spoilt sport for Newcastle 😝
— 12thkhiladi Football (@12k_football) August 19, 2023
HT: MCI 1⃣-0⃣ NEW#MCINEW #ManCity #PremierLeague #newcastle pic.twitter.com/psxb8vl2Zr
Moments later, Haaland was less precise, dragging a shot inches wide after being put in by another Foden through pass.
Newcastle's increased offensive intent in the second half only served to give City greater room to exploit from behind.
However, Haaland's uncommon night in front of goal continued.
Foden stepped up to be the creative spark in the city's midfield in the absence of Kevin de Bruyne and Silva.
The England international's turn and ball found Haaland on his preferred left foot once more, only for last season's Golden Boot winner to miss the target yet again.
Haaland tried for sheer power with his next effort but was stopped by Nick Pope's knees, forcing City to wait for a second goal to end the game.
The European champions were almost forced to pay as Rodri's poor pass gave Callum Wilson a great opportunity.
Josko Gvardiol, a 90 million euro ($99 million) defender, stopped Wilson in his home debut, while Ederson expertly stopped Harvey Barnes effort.
Guardiola, despite his team's fatigue, refused to make a single change and, when compelled to, persuaded a City supporter to take his place on the bench.
The home team, though, was all grins as City maintained its perfect start to the Premier League campaign and moved into second position behind Brighton at the top of the standings.