Lucas Moura's second-half penalty was cancelled out by a late Robert Beric strike as Saint-Etienne drew 1-1 at PSG in Ligue 1 on Friday.
After losing 3-1 at Monaco before the international break, the pressure was on PSG to get back to winning ways, with Lucas Moura's second-half penalty looking to have settled the match.
PSG had won their last 10 games against Saint-Etienne in all competitions, but the hosts scarcely threatened to break the deadlock in what was a strangely muted performance.
Lucas then seemingly secured the points for PSG after 67 minutes, coolly converting a penalty after Blaise Matuidi was adjudged to have been impeded by Kevin Malcuit, but Saint-Etienne hit back in added time.
Malcuit raided down the right and his cross was misjudged at the back post by Thomas Meunier, giving Beric time to control on his chest and fire a shot into the ground and past Kevin Trapp.
Edinson Cavani and Angel Di Maria both started on the bench, with Unai Emery having an eye on Tuesday's Champions League match at home against Arsenal.
With Saint-Etienne sitting deep, PSG were restricted to shots from distance in the early stages, right-back Meunier testing Stephane Ruffier with an ambitious strike in the 10th minute.
Henri Saivet's shot from the edge of the box was then deflected off-target by the head of Marquinhos, before a Fabien Lemoine cross deceived Trapp and floated just wide of the goalkeeper's left-hand post as the visitors threatened.
Sloppy play from Layvin Kurzawa led to a chance for Saivet after 25 minutes, but Trapp made the block at his near post.
PSG's first big chance fell to Hatem Ben Arfa, playing up front in place of Cavani, but the forward was denied by Ruffier after jinking around Loic Perrin inside the box.
Grzegorz Krychowiak was introduced at half-time to make his PSG debut, but the hosts still struggled for tempo and lacked a focal point in attack, with last year's 50-goal hero Zlatan Ibrahimovic badly missed.
Lucas had a terrific opportunity to break the deadlock after 61 minutes, but when he attacked a fine cross from substitute Di Maria the ball cannoned wide off his shoulder.
But midway through the half PSG and Lucas were handed a golden chance when referee Benoit Bastien awarded a penalty for Malcuit's foul on Matuidi, although contact seemed to be outside the box.
Lucas stepped up and sent Ruffier the wrong way, rolling the penalty into the goalkeeper's bottom-right corner.
Substitute Cavani, playing in his 100th Ligue 1 game, almost scored a spectacular second with five minutes to play but Saint-Etienne struck on the break.
Beric was left unmarked in the area and he took Malcuit's deep cross on his chest before rifling in a finish to earn his team a dramatic draw.
Key Opta stats:
- PSG have lost only one of their last 41 home games in Ligue 1 (W32 D8), against Monaco in March (0-2).
- This is the first time Hatem Ben Arfa hasn't scored while starting a Ligue 1 game at Parc des Princes, after scoring four goals in three starts with Lyon, Marseille and Nice.
- Saint-Etienne have scored four of their six goals in Ligue 1 2016-17 from the 81st minute.