Bayonne are the new outright leaders of Top 14 after their Round 5 victory away at Bourgoin lifted them a point clear at the end of a frenetic three-game spell in nine days.

Bayonne's win was their fourth in five matches, but the topsy-turvy nature of this season's results continued with Brive hammering troubled Toulon, and pre-match leaders Stade Francais going down away to a Biarritz side which had previously suffered it's worst league start for five years.

Biarritz went into their home clash with the high-flying Parisians having lost three games in succession, but a 14-point haul from international scrum-half Dimitri Yachvili laid the foundations for a morale-boosting 19-11 triumph.

Yachvili initially traded penalties with his Stade and France counterpart Julien Dupuy as the two sides went into half-time at 6-6, but a dominant second period by the Basques brought its reward as they went on to register a well-deserved win.

The home side used the strong following wind to their advantage after the break, especially once Argentine lock Manuel Carizza went over for the game's opening try just three minutes after the restart.

Yachvili duly added the extras to make it 13-6, and Stade's hopes of a comeback appeared to vanish once replacement scrum-half Noel Oelschig - on for the injured Dupuy - was yellow carded shortly after for taking out Imanol Harinordoquy without the ball.

Yachvili slotted the ensuing penalty to open up a 10-point advantage, but Stade refused to cave in and Mathieu Bastareaud then barged over for his third try of the season to breathe new life into the contest with 14 minutes left to play.

The final word was left to Yachvili though, with the home side's talismanic scrum-half landing a long-range drop-goal soon after to seal the win and get Biarritz back on track after a testing opening to their 2010/11 campaign.

Troubled Toulon continue to struggle, however, with their latest reverse - their third of the season - being a 27-9 drubbing away to a Brive side which began the afternoon way down in 12th position.

The Limousin club were gifted the early initiative after Australian centre Mafileo Kefu was handed a straight red card in the fifth minute of the match following a crude high-armed tackle which unnecessarily hindered Toulon's efforts.  Playing 85 minutes a man down was always likely to prove a tough ask after that, although the visitors initially held out as they went into half time tied at 6-6 after two Jonny Wilkinson penalties cancelled out a brace from Brive's Mathieu Belie.

The home side bulked up at the interval with two new props entering the fray and their continuing domination eventually paid dividends when flanker Gerhard Vosloo touched down five minutes after the restart. Belie added the conversion and although Wilkinson subsequently kicked his third penalty of the evening, Brive finally pulled clear as understandable gaps emerged in Toulon's defence during the closing quarter.

Replacement lock and former captain Simon Azoulai went over for Brive's second try with 15 minutes remaining and the hosts capped a superb afternoon when France international Alexis Palisson then sealed the attacking bonus five minutes later. The full-back went on to convert his own score, with Toulon's misery compounded when scrum-half Pierre Mignoni - on as a second-half replacement - went off injured with a knee problem in the closing stages.

  Leading try and point-scorers in Top 14

Elsewhere, SU Agen completed the most dramatic comeback of the day as last season's ProD2 champions rallied from 0-20 down at half-time against Perpignan to grab a share of the points following their 23-23 draw.

There was no real hint of the drama to follow as the Catalans cruised into comfortable early control thanks to the unerring boot of full-back Jérôme Porical and a 21st-minute try from young centre Jaffrey Michel. Porical couldn't land the conversion, but he did manage four successful penalties, to sit alongside Gilles Bosch's drop-goal on the half hour.

That all added up to a 0-20 half-time advantage and what looked like being a regulation away win for the 2009 champions, only for the hosts to respond with a dramatic three-try spell in 15 minutes after the resumption.

Romain Edmond-Samuel began the fight back when he touched down on 44 minutes, and the Agen recovery gathered further momentum after scrum-half Sylvain Dupuy followed suit just six minutes later. Crucially, as it later turned out, both conversions were missed, but fly-half Valentin Courrent did manage a 54th-minute penalty before Australian centre Junior Pelesasa went over for Agen on the hour mark. Courrent did manage the conversion this time, to leave the match on a knife-edge at 20-20, and the former Biarritz player then added a drop-goal soon after as Agen took the lead for the first time on Sunday afternoon.

Perpignan were temporarily down to 14 men by then following Ovidiu Tonita's 61st-minute yellow card, but they still managed to do enough to draw level once more when Porical landed his fifth penalty success of the match on 70 minutes to at least earn a share of the points.

Bayonne, meanwhile, became the weekend's only away winners as they made it four victories from five following their 23-28 success at basement club Bourgoin. To make matters worse for the home side it former Bourgoin favourite Benjamin Boyet kicked 14 points for the triumphant visitors.

The influential fly-half initiated the scoring with a trademark drop-goal in the second minute, and the Basques then assumed early control as South African import Joe Pietersen touched down for his first try for the club just two minutes later as they went 0-10 up in the blink of an eyelid.

Bourgoin's Alberto Di Bernardo then kicked three successful penalties as the home side found its feet, and Bourgoin even took the lead shortly before half-time following a 36th-minute try from jean-Francois Coux while Bayonne were down to 14 men after Rob Linde's yellow card.

Boyet's 40th-minute penalty response ensured there was 16-16 parity at the break, but it was Bourgoin who scored first after the interval when Tone Kopelaini touched down two minutes into the second half.

Di Bernardo's conversion briefly put them seven points ahead, only for subsequent tries from Abdelatif Boutaty and Yoann Huget to steal the win for Bayonne as they continue their impressive start to the 2010/11 season.

They are now one point clear of European champions Stade Toulousain after Guy Noves' side ran riot against a helplessly outclassed La Rochelle side. The home team ran in seven tries during their 50-3 romp, with full-back Maxime Médard beginning the rout when he touched down for his fourth of an increasingly prolific season after just two minutes of play.

Fly-half David Skrela missed the conversion, but he was on target following further first-half tries from young centre Rémi Lamerat, new scrum-half Nicolas Vergallo - his first for the club - and exciting flanker Sylvain Nicolas.

Stade continued to build on their 29-3 interval lead after the break, with further tries from Virgil Lacombe, Nicolas Bézy and William Servat as La Rochelle struggled to keep pace. The visitors didn't help themselves by having two players - Jacob Franck and Sefulu Gaugau - sin-binned in the second half, and only a plethora of replacements prevented further humiliation.

Defending champions Clermont Auvergne were also convincing winners, beating giant-killers Montpellier 27-10 as tries from Davit Zirakashvili, Julien Malzieu and Jamie Cudmore finally did for the Mediterranean side.

Montpellier had beaten Racing, Perpignan and Stade Toulousain in their previous three games, but head coach Fabien Galthié appeared content to accept defeat in this match as he severely re-jigged his starting XV for their third match in nine days.

Despite that Montpellier did briefly threaten yet another upset after 19-year-old winger Pierre Berard touched down on 17 minutes to give them a 7-8 lead, with the subsequent conversion from Benoît Paillaugue extending that advantage further.

Their lead only lasted five minutes, however, before a Brock James penalty brought Clermont level. The Australian fly-half added a second just before half time, with Malzieu's try on the whistle handing 'Les Jaunards' an 18-10 interval lead.

Montpellier's dogged defence then held firm throughout the second half until Canadian lock Cudmore finally broke through in the dying seconds to seal the win, with James adding the conversion to complete an afternoon of 100% success with the boot.

Sunday's other match saw Castres beat Racing-Métro 31-25 thanks to 26 points from the boot of prolific full-back Romain Teulet. Fijian Sérémaia Bai grabbed Castres' only try of the afternoon following a dazzling show of individual skill, while Racing at least grabbed a defensive bonus thanks to a last-gasp drop-goal from Juan Martin Hernández.

The Argentine marked his first start fro Racing with a 20-point match haul, alongside Benjamin Noirot's 65th-minute try.