Oualid El Hajjam's ninth-minute header had the hosts on top but their delight was cut short 10 minutes later when Achraf Hakimi smashed in a first competitive goal for his new club.
Mauro Icardi doubled the lead two minutes later with what proved to be the winner, poking past goalkeeper Gauthier Gallon after good work by Kylian Mbappe.
Amid speculation over the possible arrival of Lionel Messi in Paris, Mauricio Pochettino's side started positively on the field as it looks to recapture a Ligue 1 crown which it has claimed in seven of the past nine seasons.
Thilo Kehrer's last-ditch intervention made amends for centre-back partner Presnel Kimpembe's early mistake as Troyes threatened, though PSG did not escape so lightly from the resulting corner. El Hajjam greeted Dylan Chambost's inswinging delivery as the centre-back nodded past Keylor Navas.
Ander Herrera sent a rising effort into the side netting but shortly after Hakimi restored parity, powering onto Herrera's pass before blasting a right-footed volley into the roof of the net.
Things rapidly worsened for the hosts when Icardi added a second, the forward prodding home after Mbappe's cutback found his team-mate inside the area.
Mbappe thought he had scored himself when he rounded Gallon and curled towards goal, only to be denied by Jimmy Giraudon's goal-line clearance.
Renaud Ripart induced a smart reflex save from Navas to keep out a drilled strike that seemed destined for the net, while Mama Balde's audacious acrobatics had the PSG goalkeeper scrambling after the break.
Back-to-back opportunities followed for the away side to finish the game off but neither went in, Icardi flicking a header wide and Mbappe bending a shot narrowly over the crossbar.