And rightly so!
I had both games (as a 12-year-old I asked my parents to buy me FIFA as, you know, I came all the way from FIFA International Soccer... Then tried ISS and decided there was no match, so I got it too with my hard-earned tips as my parents rightly wouldn't buy me both of them) so I can definitely confirm this is the case.
Anyway, do you perhaps remember which review it was (or maybe also have a link)? Curious to read that if it's still around. 😄
He said a magazine, plus 90's so i think a link is impossible.

I can also confirm, and now it makes sense to what
@Madmac79 said before, that for some reason back in 1996, being 10yo, I did knew FIFA but not ISS, no advs no promo about ISS.
It was XMAS of 1996 and my father asked me to order an Snes game for present. I needed a footy but I was knowing only FIFA, so I ordered whichever FIFA he finds.
He came a night after work, giving me my present, but it was something unknown. ISS name, two cartoony players in the label, no FIFA logo...He did not find FIFA 96 or 97 and the shop clerk suggested to buy ISS instead of some older FIFA.
OMG, I said. I can't describe my little child's heartbroken disappointment. On the one hand I tried to be polite cause it was XMAS and cause my father very rarely bought me video games, although he was a gamer in his youth, last game he played was in the 80's the DK with DKong as villain and Mario/Jumpman as the hero.
But I felt totally wasted and depressed, I was thinking, my present chance was fakin wasted, I must wait until nameday or birthday for a new chance, 4 and 7 months latter respectively.
My father seeing the disappointment in my face told me that he knows this KONAMI company (lie) and that they are goodfame developers, my father is a computer programmer too, and proposes to boot up and play a 2p VS. Me still having the screens of FIFA in my memory, cause I had rented in from a video club last summer, agreed to play only one game just to please my father. Usually the opposite was happening, me begging for one game and parents say only one.
We booted up, he picked Germany, I picked Netherlands, second shock here, the players were "unknown". My father contributed to my shock, trying to explain that maybe they couldn't afford licensing etc.
In my 10yo brain all those sounded extra-terrestrial, my only thought was, I got an unnamed soccer, with cartoon game cover, only NT teams and freaking fake players!!! What a disaster...
The rest is history..

We played two games, GER-HOL and BRA-ARG, then he got tired, I stayed and played 1pVScom, many matches up until late night, thanks to XMAS!!! I was so extatic fascinated by the gameplay, felt so jaw-dropping. And I could not even score a goal. The next day I played all day long, trying to score just a goal, and achieving it after the first 20 matches I think.
Then I loved Allejo, Gomez, Branco, Ferreira more than the original Selecao!!! After I played ISS deluxe, ISS 64 and 98 on N64, which was the second jaw-dropping moment in my football gaming life. On 2001 I finally got my own N64 with ISS2000, then PSX with all ISS pro and PES 1 & 2. Finally the last real jaw-dropping moment was the PES 3 on PC.
But it was funny that a lie told to me by my father "those Konami are OK guys, whatever they create is good" as an excuse, defined my early video gaming life. They had awesome games to be honest, CastelvAnia, TMNT, Goemon, NBA give an'go. Whatever video game of Konami i bought, I never doubted about it!
Only until after I bought Pes2008 for PC...