Paris Saint-Germain escaped a costly slip-up in the Ligue 1 title race as Edinson Cavani's 80th-minute penalty earned a hard-fought 1-0 victory over a resilient Nancy at the Parc des Princes.
Cavani, selected from the start despite a trip to Barcelona in the Champions League to come on Wednesday, struck his 27th league goal of the season from the spot to keep the pressure on leaders Monaco, who entertain Nantes on Sunday.
It could have been a very different outcome for the defending champions, though - visiting substitute Alexis Busin saw his shot strike both posts before rolling away from goal with 15 minutes remaining, a matter of centimetres potentially playing a huge part in PSG's title challenge.
Unai Emery's side, without the rested Marquinhos and with Blaise Matuidi and Julian Draxler among the substitutes, lacked the creative quality that saw them put five past Classique rivals Marseille last time out.
The match started positively as Lucas Moura drove through the heart of Nancy's defence and into the box, but Chernik and centre-back Modou Diagne combined to turn his effort away in the seventh minute.
Emery's side struggled to break down their opponents, but Javier Pastore's searing volley was punched clear from the near post by the alert Chernik before the half-hour mark.
2008 - Gonçalo Guedes is the 1st player to start for in Ligue 1 since Pedro Pauleta on 17 May 2008 v Sochaux. Heritage. March 4, 2017
The breakthrough for PSG appeared to have come when Diallo Guidileye put Lucas' corner into his own net, but the referee's assistant signalled that the delivery had gone out of play before swinging back in.
HALFTIME: No goals to speak of between PSG and Nancy after 45 minutes. We're scoreless at the break March 4, 2017
The hosts began the second half with renewed vigour and Cavani headed wide from close range, before Chernik stopped Aurier guiding Marco Verratti's throughball inside the near post.
Aurier turned creator after the hour-mark when he surged to the byline and floated a cross to Guedes, who was denied his first PSG goal by a crucial block from Diagne.
The hosts were fortunate not to fall behind when Youssef Ait Bennasser led the break from an opposition corner and teed up Busin, who was denied by both posts.
It proved a costly miss for Nancy, as Cavani converted from the penalty spot after Chernik brought down the rampaging Aurier.
Chernik used his foot to stop Pastore adding to the scoreline, while Youssouf Hadji's fierce drive from the right-hand side of the box flew narrowly over with two minutes remaining as PSG scraped the victory.
