Manchester City left the Dragao with a 2-0 victory and their first three points of the new Champions League campaign. Erling Haaland's second-half double ended Porto's 33-match unbeaten home run and gave Enzo Maresca a successful debut in the competition as City manager.
The visitors held 64% possession and created considerably more chances. Porto had five shots without hitting the target, while City's 20 attempts repeatedly tested Diogo Costa. The home goalkeeper's saves nevertheless kept the first half goalless.
The breakthrough came soon after the interval. Haaland met Enzo Fernandez's cross in the 47th minute, heading the ball in off the post. Porto briefly increased the tempo in search of an equaliser but could not turn that spell into enough danger. Maresca introduced Elliot Anderson to strengthen City's control in midfield.
As Porto pushed forward late on, City used the space left behind. Haaland completed his double from Rayan Ait-Nouri's pass in the first minute of stoppage time. Ayyoub Bouaddi also drew attention on his first start for the club. The performance showed City's ability to manage a difficult away fixture, although converting chances earlier would have reduced the uncertainty before the second goal.