Pochettino landed the gargantuan gig in January and won his first trophy within two weeks of his appointment being announced, and also won the Coupe de France last term.
He has an army of top talent in his squad, with PSG recruiting the likes of Lionel Messi, Sergio Ramos and Gianluigi Donnarumma in the summer.
However, things haven't always gone his way on the pitch.
The capital club's grip were pipped to the Ligue 1 title by Lille last season, while they were well-beaten by Manchester City in the Champions League semi-finals.
McCoist suggested Pochettino is 'losing his sparkle', likening him to Jose Mourinho, whose success has also dried up since his early years in management.
"I watch Pochettino now in his interviews - and I remember we used to speak about Mourinho losing his sparkle," McCoist told talkSPORT.
"In interviews I've seen with Pochettino, I think he's lost that glint in his eye, the smile…
"I don't whether it's the pressure. Clearly it's a massive, massive job with a lot of pressure an unbelievable amount of pressure. It may be affecting him a little bit.
"How they never won that league last year, Lille were tremendous of course, but that's a league you'd think they should automatically be winning."