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Haaland's header in the 56th minute helped Pep Guardiola's side finally breach Napoli's defensive rearguard, after its captain Giovanni Di Lorenzo was sent off in the first half.

The City number nine reached 50 goals in the Champions League in just 49 matches, the quickest any player has achieved that feat in the competition's illustrious history.

Haaland also played a key role in the incident that led to Napoli being reduced to 10 men, with Di Lorenzo given his marching orders for chopping the Norwegian down as the last defender in the 21st minute.

Referee Felix Zwayer initially waved away City's protests, but he overturned his decision after being sent to the pitchside monitor, with Antonio Conte forced to reshuffle his pack.

The unfortunate man to be sacrificed was the returning Kevin De Bruyne, whose reunion with City lasted just 26 minutes before being replaced by Mathias Olivera.

Napoli held firm until the break, with visiting goalkeeper Vanja Milinkovic-Savic making two stunning stops in quick succession to deny Nico O'Reilly and Josko Gvardiol, before Matteo Politano cleared Tijjani Reijnders' effort off the line. 

However, Haaland struck his milestone goal 11 minutes after the restart, looping a header over Milinkovic-Savic following Phil Foden's brilliant scooped pass over the top. 

Jeremy Doku made the result safe after the hour, brilliantly beating three defenders inside the box before picking out the bottom-right corner.

City is next in action in Europe on 1 October away to Monaco, though its eyes will be firmly fixed on the highly-anticipated Premier League clash with Arsenal on Monday.