Two late goals from Edinson Cavani spared Paris St Germain from defeat but the Ligue 1 champions lost their perfect home record with a 2-2 draw against Guingamp.
In the club's first match since it was announced that Unai Emery would be leaving his position as PSG manager at the end of the season, the visitors stunned the Parc des Princes by taking a two-goal lead.
Ludovic Blas deservedly put Guingamp in front late in the first half with a superb 20-yard strike and Jimmy Briand struck a second goal after 68 minutes.
PSG, who before tonight had won all 17 home games in Ligue 1, got back into the match through Cavani's penalty in the 75th minute before the Uruguay striker headed the equaliser with eight minutes left.
Emery's side pushed for a winning goal but could not make a breakthrough, with Nicolas Benezet actually going closest for the visitors with a curling effort in injury time.
Guingamp dominated the first half and created a handful of decent scoring chances.
Briand curled an effort just off target from the edge of the box before somehow managing to head the ball into the ground and over the crossbar from six yards out shortly afterwards.
Giovani Lo Celso rushed and dragged his shot wide as PSG threatened for the first time after 16 minutes following a swift break led by Kylian Mbappe.
Back at the other end, Guingamp continued to look dangerous and Thiago Silva cleared the ball off the line from Benezet's strike before Marcus Thuram flicked the ball against a post after half an hour.
Layvin Kurzawa should have done better than head the ball wide from Angel Di Maria's cross just before half time, before Guingamp were rewarded for their endeavour.
Clement Grenier's corner was cleared only as far as Blas just outside the penalty area and the midfielder sent a stunning strike, cutting across the ball with his left foot, into the top corner via the underside of the crossbar.
PSG trudged off to boos from their supporters at half-time and they began the second half with menace.
Mbappe had the ball in the net but it was ruled out for offside. The same player then poked a cross from substitute Javier Pastore against the post as the hour mark loomed.
Guingamp were holding on but stunned the Parc des Princes into silence after 68 minutes when Briand sneaked a shot under Alphonse Areola after Lo Celso had lost the ball in a dangerous area.
PSG were staring down the barrel of a defeat and they were fortunate to be handed a way back into the match with 15 minutes remaining when Briand scythed down Lo Celso.
The challenge was clearly made outside the area but the referee pointed to the penalty spot and Cavani confidently tucked away the spot-kick.
The host were now in the ascendancy and they were level after 82 minutes when Cavani headed home a cross from substitute Thomas Meunier.
Emery's side pushed for a winning goal without really threatening Guingamp, who nearly nicked all three points themselves when Benezet's curling effort went narrowly wide.