Foden put the visitors 2-0 up with a delicate dink inside 15 minutes before setting up sub James McAtee for his side's fourth.
The England star had to be patient in his return to club football after Euro 2024, with a virus slowing his prep for the season.
But he looked back to his best in the Slovakian capital, as City picked up their first Champions League win of the season, following a 0-0 draw with Inter Milan a fortnight ago.
Phil Foden won Player Of The Match in City's first Champions League win of season
Celtic boss Brendan Rodgers says he needs to find a way to "inspire the players again" after the 7-1 thrashing by Borussia Dortmund.
We went in high in confidence. We felt we were in a really good place. We had to start much better than we did, as we gave away really cheap goals.
And we got punished for loose bits of play and passes. They were ruthless in their finishing. It was incredible to see.
It's very difficult for us to get to that level. It's a different level, with the greatest respect. We want to be more competitive, that's what was disappointing from our perspective.
My job is to go away and inspire the players again. We need to learn from it or we will get punished at this level.
Arsenal boss Mikel Arteta claims the impressive Champions League victory over Paris Saint-Germain proves his team can compete with everybody.
I think it raises the confidence and the belief that we can compete with any team at this level in games that are very different to the Premier League.
We showed maturity and put our stamp in Europe against the top teams. I really liked that.
I sensed something different in [the players] tonight. They wanted to prove a point. We can be ourselves and this is another step. We have to carry on with doing that.
I think they needed this. I think it's a special night against a big European club. It lifts the belief and spirit of everybody. It shows we can beat them.
Manchester City boss Pep Guardiola stated Phil Foden is "still not at his best" but he's "on his way back".
We said at half-time we needed one more goal and 3-0 would make it almost over. They started with a bit more courage, with four at the back, but after we went 2-0 up they sat back more like many teams.
Ilkay [Gundogan's] game at Newcastle wasn't really good, maybe one of the worst I have seen from him but in his position, holding midfield, he is really intelligent and played a fantastic game today.
Phil Foden is still not at his best, he scored a really good goal - pass the ball to the post, don't shoot. He had more chances, but he's on his way back.
Arsenal boss Mikel Arteta praised Kai Havertz and described him as a "main player".
Really, really happy with the performance. We played an opponent that has a lot of personality, is really difficult to deal with when you don't have the ball.
The first half was very dominant and we created a lot of chances and then the second half was a different story.
We suffered much more than we should have done. The Champions League brings different demands but I think we handled it really well."
He has been unbelievable. His football brain, the way he understands space, his timing, he brings people together. Hs work ethic is incredible and now he is a real threat around the box. He is one of our main players at the moment.
Erling Haaland passed another Champions League milestone - as he left Sergio Aguero trailing in his rear view mirror.
The Norwegian forward latched onto a lovely through ball from Rico Lewis and finished with the minimum of fuss just before the hour.
That was a 42nd goal in just 41 appearances in a competition that the £51.4million buy admits he loves playing in.
That takes him past City’s all-time leading scorer Aguero’s tally in Uefa's most presitigious tournament – and don’t forget Haaland is still only 24.
He was subbed a few minutes later and might have felt slightly annoyed with Pep Guardiola – as there were more goals in this one for him.
This was little more than a training exercise for the English champs against the Slovakian rookies – and the only surprise was they only scored four.
But after a draw in their first European game against Inter Milan two weeks ago, they are well and truly up and running now.
Slovan had played eight games just to reach the league stage of the competition – and on their opening night a fortnight ago they were thumped 5-1 by Celtic in Glasgow.
Yet they were thrilled to be welcoming the 2022/3 winners and all the star names to their home and were determined to enjoy the night.
Arsene Wenger used to moan until the cows came home about the impossibility of competing with state-owned oil-rich clubs.
Mikel Arteta simply gets on with it - and with increasingly impressive levels of success.
Having given Abu Dhabi’s Manchester City a serious fright in a 2-2 draw at the Etihad nine days ago, here were the Arsenal strolling to victory against the pride of Qatar, Paris Saint-Germain.
It helped that PSG keeper Gianluigi Donnarumma went a long way to gifting first-half goals to Kai Havertz and Bukayo Saka.
But Arteta’s side - unbeaten in four against Pep Guardiola’s City by the way - are looking increasingly comfortable back on the Champions League stage which they vacated during Wenger’s latter years.
This was a battle between arguably the two most famous European clubs never to have ruled the continent - and on this evidence, Arsenal look far closer than the French champions to finally lifting Old Big Ears.
