Clermont Auvergne failed to return to the Top 14 summit as Stephen Brett's last-gasp penalty was only enough to earn a 23-23 draw against Bordeaux-Begles.
Clermont were displaced at the top after La Rochelle triumphed 23-20 in their match against Toulon on Saturday, and Brett's 81st-minute kick means they now trail the new leaders by a point.
An impressive start saw Luke Braid and Yann Lesgourgues cross within 18 minutes as Bordeaux took a 14-3 lead into half-time.
Brett converted tries by Benson Stanley and Sitaleki Timani to haul Clermont level, but Ian Madigan put Bordeaux three points clear from the tee in the 73rd minute.
Clermont continued to push and got their reward when Brett split the posts.
Bottom side Bayonne earned just their fourth victory of the season by defeating Brive 33-23 at Stade Jean Dauger.
Bayonne made the most of a yellow card for a professional by Petrus Hauman in the 66th minute with the score 19-16, following up a penalty try with a score from Martin Bustos Moyano that put them out of reach in the closing stages