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.

The Uruguayan made no mistake from 12 yards, punishing Nancy for a rare error that saw goalkeeper Sergei Chernik send Serge Aurier tumbling inside the box as the match looked destined to finish as a dour goalless draw.

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.

Nevertheless, PSG ground out the win to move level with Monaco on 62 points and avoid the possibility of dropping to third by the end of the weekend.

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.

PSG dominated possession but Faitout Maouassa offered a warning with a brilliant 25-yard drive that Kevin Trapp did superbly to push away from the top-left corner.

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.

Pastore then created a chance that Cavani was unable to dink on target, with Goncalo Guedes only finding the side netting from an acute angle as it headed out of play.

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.

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.