Coming off their away-goals Champions League exit to Barcelona, PSG seemed to find the Stade de l'Aube somewhat less inspiring than the Nou Camp and afforded Troyes the better chances in the first half.
However, Blaise Matuidi's 65th-minute strike eventually sank his former club to send PSG 10 points clear of Marseille, who travel to Lille on Sunday.
In the race for the European spots seventh-placed Montpellier suffered a blow as they lost 4-2 at Bordeaux.
Les Girondins stormed into a 3-0 lead inside the opening half-hour through goals from Ludovic Sane, Cheick Diabate and Jaroslav Plasil and Henri Saivet added a fourth in the second half after Remy Cabella had pulled a goal back for Montpellier.
Benjamin Stambouli added a second for Montpellier late on but it was too little for the defending champions who remain four points behind fifth-placed Lille. Bordeaux are a further two points back following their win.
Lorient breathed life back into their fading European hopes with a deserved 4-1 victory over in-form Bastia, closing to within a point of Montpellier in the process.
Christian Gourcuff's Lorient had slipped to eighth after winning just once in six matches but they picked up a maximum haul on Saturday night thanks to goals from Yann Jouffre, Benjamin Corgnet and a late brace from Jeremie Aliadiere.
Mid-table Bastia, who had won four of their previous five matches and scored 12 goals in their last three, had pulled a goal back when 2-0 down through Anthony Modeste but that was all they had to show for their trip to the Stade du Moustoir.
At the other end of the table, Evian and Reims both boosted their hopes of avoiding the drop with victories.
Evian downed Rennes 4-2 at home with late goals from Milos Yinkovic and Yannick Sagbo moving them three points clear of the relegation places.
Earlier Evian had twice squandered the lead, with Jean Kana-Biyik's own goal and Kevin Berigaud's strike scrubbed out by Julien Feret and John Boye.
Reims, meanwhile, are three points better off than Evian after continuing their good recent form with a 2-0 win over Brest.
Nicolas Fauvergue and Diego netted the goals to consign second-bottom Brest to a fifth successive defeat.
In Saturday's other match, relegation rivals Nancy and Ajaccio shared a 1-1 draw.
Third-bottom Nancy, who for so long looked doomed to relegation this season, have enjoyed a resurgence in recent weeks and came into today's encounter seeking a sixth win in seven.
Patrick Gabriel's side began brightly with Paul Alo'o putting them in front inside five minutes, but they were swiftly pegged back by Mehdi Mostefa's leveller as the points were shared.