Bayonne could not follow up their opening-day win over Racing 92 with another Top 14 victory despite an outstanding first half at home to Clermont Auvergne on Saturday.
The newly promoted side had announced themselves back in the top flight with an impressive maiden triumph and it initially appeared as though they would make it two from two this week.
However, Clermont, last season's runners up, rallied to win 34-30.
The visitors were stunned by a pair of early tries from Maxime Lamothe and Peyo Muscarditz.
Clermont followed up four first-half penalties with a try of their own through George Moala to briefly lead but they trailed heading into the interval thanks to Julien Tisseron's five-pointer.
Last week Bayonne improved after half-time, yet this time their fortunes took a turn for the worse and Guillaume Rouet swiftly went into the sin bin.
The hosts still held on for a time, but Apisai Naqalevu and Charlie Cassang crossed to take the game out of Bayonne's reach.
There was first-half entertainment between La Rochelle and Stade Francais too, with four tries and two yellow cards - all shared evenly between the sides - before the break.
La Rochelle clung on to win 28-26 despite a pair of tries for Stade in the final five minutes.
Montpellier played for close to an hour with just 14 men but still ran in a big 43-22 success against Pau.
Youri Delhommel, who opened the scoring, was sent off for a dangerous tackle on Antoine Hastoy, yet that did not slow Montpellier and their task was made easier late in the second half by two Pau yellow cards in as many minutes.
Elsewhere, Agen kept Brive waiting for their first victory back in the Top 14, winning 16-10, while Bordeaux-Begles saw off Toulon 34-12.