Yachvili played the first of his 42 French Tests against Canada in 2002
Dimitri Yachvili inspired Biarritz to a convincing Heineken Cup bonus point win over the Dragons as the French side took control of Pool Two.
The France scrum-half's 22-point haul in a 49-13 triumph moved the unbeaten leaders nine points clear and on the verge of quarter-final qualification.
Yachvili scored one of Biarritz's six tries and kicked 17 points in the win.
Former Lions and England full-back Iain Balshaw scored twice for the hosts before Tom Riley's late consolation.
The Dragons suffered their heaviest Heineken Cup defeat since they crashed 37-0 to Stade Francais in 2003 as Biarritz confirmed credentials as potential European conquerors this season.
The French side, beaten finalists three years ago, battered the Dragons into submission up front as wing Takudzwa Ngwenya and substitute Valentin Courrent touched down for Biarritz while they were awarded a penalty try.
And to add insult to injury, key players flanker Dan Lydiate and full-back Jason Tovey suffered knocks and could join Wales lock Luke Charteris on the sidelines for Friday's return at Rodney Parade.
While Biarritz have sometimes struggled on the road in Europe, the Dragons face a considerable psychological challenge to transform their fortunes after this six tries to one thrashing.
Centre Riley was the only scorer for the shell-shocked Dragons while fly-half James Arlidge kicked the conversion and two penalties.
The Dragons, beaten on all five of their previous Heineken Cup trips to France, fell behind to an early Yachvili penalty.
And assisted their own downfall when Hugh Gustafson was sin-binned for a professional foul before his fellow prop Peter Bracken committed a high tackle and Yachvili booted the resulting penalty.
The Dragons encountered a torrid time in the scrums, where France prop Fabien Barcella proved particularly destructive, and the visitors conceded an 18th-minute penalty try that Yachvili converted.
But matters soon deteriorated further for the Dragons, who saw number eight Grant Webb yellow-carded and then conceded two tries during a damaging three-minute spell.
Magnus Lund created the first, catching the restart following an Arlidge penalty and sending Yachvili over, before Ngwenya intercepted an ambitious midfield pass and sprinted 40 metres unopposed.
It a damage-limitation exercise for the Welsh team in the second half but they were powerless to prevent Biarritz from claiming a bonus-point try just five minutes after the break.
Balshaw was the beneficiary of more mighty work by the Biarritz pack, touching down wide out with an overworked Dragons defence once again shredded.
Dragons coach Paul Turner began making changes from the bench, but it had little impact as a sharp Yachvili break and well-placed kick enabled Balshaw to claim his second try.
Dragons coach Paul Turner said: "It was disappointing and we have to grow up in five days.
"We talked about not allowing Biarritz momentum and we presented them with momentum as we gave them nine penalties and you can't do that against sides of this quality.
"That gives them launches and from their launches the game went away from us very quickly and I felt for our players but it was experience for a lot of them
"We were second best and every time they got near our 22-yard line they punished us. We made a lot of errors and we were punished and you don't get punished like that very often."
Biarritz: Balshaw, Ngwenya, Hunt, Traille, Bolakoro, Peyrelongue, Yachvili, Barcella, August, Hughes, Thion, Taele-Pvihi, Lund, Vahafolau, Faure. Replacements: Brusque for Ngwenya (42), Mignardi for Hunt (70), Courrent for Yachvili (61), Coetzee for Barcella (57), Terrain for August (57), Carizza for Taele-Pvihi (60), Johnstone for Lund (67), Hall for Faure (60).
Newport Gwent Dragons: Tovey, Brew, Gomer-Davies, Riley, Fussell, Arlidge, W. Evans, Gustafson, Goodfield, Bracken, A. Jones, Sidoli, Lydiate, G. Thomas, Webb. Replacements: M. Thomas for Tovey (45), Walker for W. Evans (59), Willis for Goodfield (50), Robinson for Bracken (46), Bearman for A. Jones (53), McKenzie for Webb (18). Not Used: MacDonald, Watkins.
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