All Blacks star Aaron Cruden had two tries disallowed as his Montpellier team suffered their first defeat of the season on Saturday, going down 47-17 at Bordeaux.
Fly-half Cruden had both scores ruled out after video replays, adding to the frustration of his team who conceded five tries -- four in the first half -- and finished with 14 men after Georgian lock Constantin Mikautadze was red-carded for planting an elbow into centre Matthieu Jalibert.
Mikautadze had only been on the pitch for 15 minutes before he was sent off, but by then the damage had been done with Bordeaux already 40-17 ahead.
"We lost today against a team who really needed the win, but we were surprised by the speed of their execution," said Montpellier coach Vern Cotter.
"All the teams at the start of the season have days when they are a little off."
Bordeaux had stunned champions Clermont in their season opener and they showed that class again on Saturday with their bonus point win.
Loann Goujon, Joe Edwards, Jean-Pascal Barraque and Apisai Naqualevu scored tries in the first 40 minutes.
Simon Hickey added a fifth try after 76 minutes as the New Zealand fly-half finished with a 27-point haul.
Fellow Kiwi Cruden converted both of Timoci Nagusa's tries for Montpellier.
Cotter's team stay top but are just a point ahead of La Rochelle, who claimed a third successive win with a 57-12 mauling of promoted Oyonnax.
La Rochelle had already seen off Clermont 51-20 and Agen 20-15 and were unstoppable on Saturday in an eight-try romp.
Alivereti Raka continued his good form as Clermont made it back-to-back Top 14 wins for the first time this season by beating Racing 92 23-21.
After two defeats in their opening three games, Franck Azema's men have recovered to close in on the top six.
Fijian wing Raka got the hosts on their way with his fifth try of the season in the sixth minute, which was converted by Camille Lopez.
Racing scrum-half Teddy Iribaren, on kicking duties in the absence of injured New Zealand great Dan Carter, cut the deficit with a penalty before adding the extras to Teddy Thomas' score to put Racing ahead.
Clermont took a 14-11 advantage into the interval though as English full-back Nick Abendanon touched down, with fly-half Lopez slotting over the conversion.
French international Lopez kicked over three penalties early in the second period to seemingly put the game to bed and take his personal haul to 13 points.
A second Iribaren penalty and a converted penalty try set up a tense finale.
Clermont were briefly down to 13 men as Fritz Lee and Raphael Chaume were sin-binned, but Racing wing Juan Imhoff also saw yellow as the home side held on for their third victory of the campaign.
"It was far from the perfect match but the victory was achieved," said Clermont scrum-half Morgan Parra.