Paris - Reigning champions Clermont slumped to a shock 32-25 defeat at Bordeaux-Begles as the French Top 14 season got under way on Saturday.
Tries from Perceli Yato and Remy Grosso gave Clermont an 18-11 half-time advantage despite Fa'asiu Fuatai's score for the hosts five minutes into his debut.
But Bordeaux dominated the second period and tries from Peni Ravai and Jean-Baptiste Dubie saw them score 21 unanswered points before Michael Simutoga's late consolation.
"Honestly, we were quite poor in our structure today, we had problems," admitted Clermont coach Franck Azema.
"In the second half, we felt that they took the ascendancy over us. They deprived us of the ball and put us under pressure little by little.
"Bordeaux deserved their victory, they were better than us, there's nothing more to say."
New Zealand sevens international wing Fuatai, a close-season signing, powered over to give the home side a perfect start, although his compatriot Simon Hickey failed to add the extras.
Fijian flanker Yato quickly responded for the visitors, with Patricio Fernandez's conversion giving them the lead.
Winger Grosso grabbed Clermont's second try in the 15th minute, before Hickey kicked over a penalty to cut the gap to just four points after a frenetic first quarter of the match.
Clermont continued to look the more threatening side though, and after a period of sustained pressure, Argentinian international Fernandez converted two penalties to put Azema's men in control.
Bordeaux spent the closing stages of the first half camped in front of the Clermont posts, but went into the break with only a second Hickey penalty to show for their efforts.
The second period started in the same vein as the first had ended, and Hickey added three more points to his tally from the tee.
The 23-year-old slotted over another penalty just minutes later to move Bordeaux to within one point, as the French champions continued an ill-disciplined display.
They were made to pay just after the hour mark, as Bordeaux's forwards rumbled over the line, with Ravai, a Fijian signed from second-tier outfit Aurillac, getting the final touch.
Hickey made a second goalkicking error though, by striking the simplest of conversions against the post, but did score his fifth penalty to make amends.
Any hopes of a Clermont revival were snuffed out with 10 minutes remaining, as winger Dubie avoided two tackles and dived over the line, before Hickey's replacement Tian Schoeman was successful with his first kick for the club to open up a 14-point lead.
Prop Simutoga gave Clermont faint hope of grabbing an unlikely draw at the death, but his try, converted by Camille Lopez, proved to be just a consolation.
Earlier on Saturday, Toulouse snatched a 23-23 draw at Oyonnax in the season-opening game, as South African full-back Cheslin Kolbe's late try and Thomas Ramos' conversion helped Ugo Mola's side avoid a shock defeat by their newly-promoted hosts.
Montpellier ran in seven tries in a 48-19 thrashing of Agen for the only bonus-point victory of the day as New Zealand fly-half Aaron Cruden made his debut.
La Rochelle, who finished top of the regular-season table last term before a semi-final defeat by Toulon, made a solid start with a 19-10 win at Brive.
Stade Francais, who saw a proposed merger with Racing 92 scrapped earlier this year, slumped to a 25-16 loss to Lyon in the capital.
Racing had no such problems, but did need a last-gasp try from Louis Dupichot, converted by former World Player of the Year Dan Carter, to snatch a 25-21 win over Castres.