At times, this did not feel like an opening game of the group stages but one to decide progression to the knock-out rounds.
There was more than a bit of bite to it – with six bookings in all, five to City players – and several flashpoints, both out on the pitch and on the sidelines. Pep Guardiola and Sergio Conceicao were complimentary about each other in the build-up but did not shake hands at the final whistle.
The Portuguese champions provided more than a stern test for one of the favourites to reach and win May’s final in Istanbul. City were in fact required to come from behind when some abominable defending allowed Luis Diaz to make a wonderful individual run and establish an early lead.
A Sergio Aguero penalty quickly restored parity, though Porto did well to contain City’s fluid attacking movement until their resistance was finally broken by a Ilkay Gundogan free-kick. A fine Ferran Torres strike made sure of all three points.
The first half was both evenly matched and ill-tempered. Porto set up in the same way as many teams that visit the Etihad – deep, defensive and looking to break upfield quickly. The difference was Conceicao’s side had the speed and the power to hurt Guardiola’s. Even so, City could only blame themselves for conceding the opening goal.
A stray pass by Ruben Dias allowed his namesake Luis to collect possession out on the left wing and cut inside towards goal entirely unopposed. The Colombian had reached the edge of the penalty area before a City player stuck a foot in and, even then, the less said about Rodri’s attempt the better.
The hesitant Joao Cancelo’s effort to win back possession was even worse and left Diaz with a difficult finish across Ederson and into the far corner. He found the angle he required to beat the City goalkeeper and score a genuinely magnificent goal, but it was an easily preventable one from Guardiola’s perspective.
At least City did not need to wait long for an equaliser, even if there was a prolonged VAR check after Pepe had barged into Raheem Sterling with his typical grace three minutes later. Gundogan had stood on goalkeeper Agustin Marchesin’s shin in the build-up, moments before striking the post.
The decision could have gone either way but went City’s, and Aguero’s spot kick beat Marchesin by inches, slipping underneath his low dive to the right. The Argentine had scored his first penalty for City in a year and his first goal since returning from successful knee surgery.
Rightly or wrongly, Porto felt aggrieved. City’s bench were also growing irritated by referee Andris Treimanis and his tendency to penalise for every potential foul. Fernandinho, sat among the substitutes, was a particularly vocal critic of the Latvian’s performance, especially when Kyle Walker, Bernardo Silva and Cancelo were all booked in the space of 10 minutes.
Composure was needed. Porto were threatening and Walker was forced to clear off his own goal-line when Marega caught Cancelo napping and broke in behind, minutes before the interval. City, by contrast, were creating little. Gundogan’s sweet volley once both sides re-emerged forced a save out of Marchesin but was only City’s fourth attempt on goal.
Without the injured Kevin De Bruyne and the departed David Silva, Guardiola’s side were struggling to create and needed a bit of luck. It came in the form of a foul by Fabio Vieira, though Treimanis had once again made a questionable call. The Porto midfielder took the ball but also caught Gundogan, who made sure to take full advantage.
There was something De Bruyne or Silva-esque about the free-kick that followed, expertly bent out of Marchesin’s reach and into the top left-hand corner. This time, there were no protests from Porto, who instead trudged back to the centre circle which their heads hung low, in sudden realisation that the contest was slipping away from them.
Guardiola was waiting to introduce Torres and Phil Foden as he watched Gundogan’s free-kick fly in. He persisted with the substitution and it brought him a third goal when the pair combined with a neat one-two down the left flank. Torres then cut inside to enter the penalty area and curl past Marchesin.
There was still time for a worrying injury to Fernandinho, who left the pitch shortly after coming on. Fortunately, by that point, the battle had already been won.