Haaland reached his half century in Europe's elite competition in just 49 appearances before Jeremy Doku ensured Pep Guardiola's men got their quest for Champions League glory off to a winning start

There was no fairytale return to the Etihad for Kevin De Bruyne as his night was cut short after just 26 minutes as a result of Di Lorenzo's dismissal.

De Bruyne was welcomed back like a hero just months after departing as one of City's greatest players in the club's history.

The Belgian's name rang around the Etihad before kick-off, while a series of banners paid hommage to the man who contributed nearly 300 goals or assists in 422 matches during his time in Manchester.

However, Antonio Conte showed no room for sentiment as he sacrificed the 34-year-old to bolster his defence with the introduction of Mathías Olivera.

Di Lorenzo's dismissal and De Bruyne's departure also neutered Napoli as an attacking force.

The visitors best chance came while they still had 11 men on the pitch as City's new goalkeeper Gianluigi Donnarumma proved his worth as a world-class shot stopper to parry Sam Beukema's header from a corner.

The game changing moment came when Di Lorenzo made a desperate lunge to prevent Haaland running clear on goal and wiped out the Norwegian on 21 minutes.

Referee Felix Zwayer initially thought the defender had got a touch on the ball but was instructed by VAR to review and correct his error.

Napoli held firm until half-time thanks to some spectacular goalkeeping from Vanja Milinkovic-Savic.

The Serbian, who had a brief spell early in his career at Manchester United, produced excellent saves to deny Rodri, Nico O'Riley and Josko Gvardiol.

Even when Milinkovic-Savic appeared beaten in first-half stoppage time, Matteo Politano got back on the line to block Tijjani Reijnders' goalbound effort.

There was only one outcome once the Napoli rearguard was eventually breached 11 minutes into the second half.

Phil Foden's flick found Haaland who looped a header over Milinkovic-Savic for his 12th goal in seven games for club and country this season.

Doku then delivered the knockout blow with a brilliant individual run past three Napoli defenders before slotting coolly under the onrushing goalkeeper.

City's season got off to an underwhelming start with two defeats in their opening three Premier League games to Tottenham and Brighton.

But Guardiola's side have steadied the ship through two-thirds of a huge week after a convincing 3-0 derby win over Manchester United at the weekend.

Ahead of a trip to title rivals Arsenal on Sunday, Guardiola could afford the luxury of resting Haaland and Rodri during the closing stages, which resembled a training exercise as City stroked the ball around at will.

The Italian champions were happy just to limit the damage in what is likely to be their toughest trip of the league phase.