Erling Haaland scored twice to hand Manchester City a 2-0 victory at FC Porto in Enzo Maresca's first UEFA Champions League game as City head coach — though the performance will have given the Italian manager little comfort ahead of Sunday's Manchester derby.

Haaland was profligate throughout the first half, squandering two close-range opportunities that Porto goalkeeper Diogo Costa saved smartly, before heading a third chance over the bar. Costa was in outstanding form, also denying Rayan Cherki from the rebound of one of Haaland's efforts in a commanding opening 45 minutes for the hosts' shot-stopper.

Haaland makes amends early in the second half

The Norwegian striker needed just two minutes of the second period to put his first-half wastefulness behind him. Haaland muscled Jakub Kiwior off the ball and nodded an Enzo Fernandez cross in off the post to break the deadlock in the 47th minute.

City then eased off the accelerator, and Porto began to grow into the game. The Portuguese champions never managed a shot on target, but Alan Varela curled an effort just wide of the far post from the edge of the area — a warning City could not ignore.

City goalkeeper Gianluigi Donnarumma then had a nervy moment in the 66th minute, nearly losing possession to Porto forward William Gomes, before the ball fortunately ran behind for a goal kick.

Stoppage-time finish wraps up the points

Substitute Rayan Ait-Nouri, who had earlier steered a shot wide when well placed, ultimately proved the architect of City's second goal. He worked his way to the byline and cut the ball back for Haaland to tuck home in stoppage time, confirming a 2-0 scoreline that flatters the visitors somewhat.

Maresca had failed to win any of his three away Champions League fixtures as Chelsea head coach last season. This result ends that run — yet with the Manchester derby at Old Trafford arriving on Sunday, City's laboured display offers a cautionary note for the manager.