PSG has won its past five games to move up to second place in the French league, with Ibrahimovic scoring six goals during that spell, and the defence conceding just two.
Carlo Ancelotti's PSG has not played a team of Porto's calibre this season and faces its first big test against the Portuguese champion, although its defenders will no doubt be relieved that striker Hulk no longer plays for the club.
Dynamo Kyiv, which has recruited Oleg Blokhin from the Ukraine national team as its new coach, hosts Dinamo Zagreb in Group A's other match, with both teams getting back to winning ways at the weekend after losing their previous two games.
Victory against Porto would put PSG well on the way to the knockout stages and raise expectations even higher after an outlay of over €150 million on new players the off-season.
"They're expecting a lot this season, which is normal given all the money invested by the club. We're working hard every day to do great things and I hope we can continue to deliver," Ibrahimovic said. "The team has a lot of pressure to play good and win all the games that are coming. Everyone is talking about us, talking about Paris Saint-Germain, and they want to beat us."
The bad news for Porto is that Ibrahimovic thinks he can still improve, even though he has already impressed enough with eight goals in six games since joining from AC Milan, along with Brazil centre back Thiago Silva.
"I had a little injury in the beginning, now I'm feeling better and better," said Ibrahimovic, who scored in a 4-1 thrashing of Dynamo two weeks ago. "I'm starting to find my rhythm. I'm not at 100 per cent yet, but that will come. I scored (a lot) because my team is doing good — without my teammates I don't score."
Porto dropped points last weekend when it was held to 2-2 at minnow Rio Ave to end its three-game winning run in the Portuguese league. It still shares the lead with Benfica, however.
Porto went off the boil in that game when key Argentine midfielder Lucho Gonzalez was substituted after 60 minutes. Gonzalez got one of the goals in Porto's 2-0 win in Zagreb in the group opener.
"I don't think this result will bother us in the Champions League," Porto coach Vitor Pereira said. "It's a different competition and I'm sure we'll be at our best."
Even without Hulk in attack — the Brazilian left for Zenit St. Petersburg in a big-money move that PSG would be proud of — Pereira is confident his team has enough firepower to breach PSG's iron defence.
"I do like him and appreciate everything he's done for the club," Pereira said. "He has his unique qualities, but the team has many talented players. We will keep on scoring."
Dinano, meanwhile, is brimming with confidence after coming back from a goal down to beat bitter rival Hajduk Split 3-1 on Saturday.
Dinamo's 16-year-old forward Alen Halilovic stood out, having a goal disallowed, and could feature against Dynamo.
"I am thrilled and I don't even know how to describe my feelings. I will always remember the moment I entered the game," he said. "This is my first of many games for Dinamo and the first goal will come, sooner or later."
Dynamo laboured to a 1-0 win against Zorya on Friday to give Blokhin a successful start after replacing Yuri Semin, who was fired on the back of successive 4-1 defeats to PSG and Shakhtar Donetsk.