In the absence of Zlatan Ibrahimovic, the attackers helped Laurent Blanc's side bounce back having gone behind early on in their pre-season friendly
PSG lost the first game of their pre-season tour 3-1 to Sturm Graz on Tuesday but looked much sharper in the encounter at the Gerhard Hanappi Stadium.
Head coach Laurent Blanc named a strong side for the game, with the likes of first-team regulars Thiago Motta, Alex and Pastore all starting. However, captain Thiago Silva and striker Zlatan Ibrahimovic were both absent.
The match got off to a bad start for the Ligue 1 champions though, as Christopher Trimmel opened the scoring for the home side after 16 minutes with an outrageous back-heeled volley that Ibrahimovic himself would have been proud of.
Trimmel attacked a corner delivery and finished impudently from six yards, leaving Nicolas Douchez in the PSG goal with no chance.
Youngster Hervin Ongenda - who scored PSG's goal in their loss to Graz - almost brought the visitors level four minutes later, but Rapid keeper Jan Novota parried his powerful effort from 20 yards away.
PSG went in 1-0 down at the break, but came out for the second half with much more purpose. Malian striker Kalifa Coulibaly hit the bar with a header after 65 minutes, but Blanc's men were level 12 minutes later when Argentina international Pastore volleyed home after Gameiro had flicked on a cross from Gregory van der Wiel.
And Gameiro himself then stole the win for PSG with a brilliant individual effort in the 81st minute.