City face another 17 games in 2020 with all six Champions League group-stage matches packed into a seven-week stretch either side of the November international break.
Guardiola’s men have struggled to hit the ground running this season with a short pre-season, coronavirus infections and injuries taking their toll.
On Wednesday City missed the presence of the injured Kevin De Bruyne, but battled back to get their latest quest to win a maiden Champions League off to a winning start after Luis Diaz’s solo effort put the visitors in front in the first half.
Sergio Aguero levelled with a contentious penalty seven minutes later and the Premier League side’s quality shone through after half-time as Ilkay Gundogan’s free-kick and substitute Ferran Torres’ fine finish moved City to the top of Group C.
“It’s a good start for us,” said Guardiola. “We knew the games at home you have to win in this competition.
“(Fernandinho) is the bad news, he has a muscular problem so he will be a big loss. In this period we need everyone, but with this calendar it happens.”
Guardiola admitted on Tuesday to still feeling guilty over the experimental line-up and formation that led to City’s latest Champions League calamity in last season’s quarter-finals against Lyon in August.
The Catalan is into the final year of his contract at the Etihad Stadium and so this is potentially his last chance to land the prize City most desired when they brought him to Manchester in 2016.
However, in the early weeks of this season City have look a faded force from the prime of Guardiola’s reign, when they won back to back Premier League titles in 2018 and 2019.
– Gundogan’s moment of magic –
A sluggish start against Porto was punished by Diaz who opened the scoring with a brilliant solo run and finish.
City levelled with a good deal of fortune when Gundogan inadvertently caught Porto goalkeeper Agustin Marchesin as he tried to direct the ball goalwards and, after the German’s shot came off the post, Raheem Sterling was barged over in the box by Pepe.
After a lengthy VAR review, Gundogan’s challenge was not deemed a foul that would have overturned the initial decision to award a penalty, and Aguero smashed home his first goal of the season.
City regained control after the break, but it wasn’t until a moment of magic from Gundogan 25 minutes from time that they went in front.
The midfielder won a free-kick on the edge of the area and then curled the ball over the wall and into the net to the relief of Guardiola, who was about to replace him.
Gundogan was starting for the first time since testing positive for coronavirus and he was replaced seconds after scoring as Guardiola added a fresh injection of pace in Phil Foden and Torres, who combined for the latter to make it 3-1 in style.
Gundogan, though, said City will need a squad effort to get through the next few months.
“We are struggling at this moment,” said Gundogan. “Fernandinho went off, we have a few injured players. Even me, I am not 100 percent because I was out with Covid for a couple of weeks.
“That’s the challenge this season and it’s not going to end for a while, but we will take every game as it comes. We have enough players who have the quality to play.”
