Lyon lost for the first time since August as Saint-Etienne stormed to a 3-0 victory at the Stade Geoffrey-Guichard.
Despite spending long spells without the ball, it was the hosts who looked most threatening early on, and they came close to opening the scoring when Ricky van Wolfswinkel headed against the post from Max Gradel's cross.
Gradel continued to make an impact on the wing, and his inviting cross allowed Moustapha Bayal Sall to head home the opening goal in the 18th minute.
Stephane Ruffier came to the rescue for Saint-Etienne midway through the first half with a fine save to deny Nabil Fekir after the Lyon forward had broken free of the home defence.
The save looked even more important five minutes before the interval when Van Wolfswinkel found the space to head in another dangerous cross from Gradel.
Saint-Etienne were inches away from extending their lead early in the second half as Loic Perrin rattled the crossbar with a firm header.
However, the home fans would be treated to a third in the 68th minute when Renaud Cohade took full advantage of confusion in the Lyon box to fire past Anthony Lopes.
The misery was piled onto Lyon late on when Alexandre Lacazette dragged a penalty wide of the post after Ruffier had sprinted off his line to bring down Fekir in the box.
