Uncapped fly-half Enzo Herve stepped in for the injured ex-Wales international Dan Biggar to guide Toulon to the summit of the French Top 14 with Saturday's 36-13 win over Pau.
Herve, 25, scored 21 points including two tries as Toulon moved above Racing 92 to top spot with experienced Biggar out since earlier this month with a back issue.
Surprise packages this season, Pau lost just for the third time in nine games this term as Australia winger Jack Maddocks crossed for his fifth try of the campaign.
Later, Racing 92 are without South Africa's two-time Rugby World Cup winning captain Siya Kolisi for a trip to Clermont and can go back above Herve's side.
Elsewhere, La Rochelle face lowly Perpignan, eight days from starting the defence of their second Champions Cup title in a rerun of last season's final by hosting Leinster.
Promoted Oyonnax host in-form Bordeaux-Begles in heavy snow in the foothills of the French Alps and controversial former French rugby federation president and ex-France head coach Bernard Laporte takes his Montpellier to Bayonne.
On Sunday, title holders and record 22-time champions Toulouse go to Paris to play Stade Francais, winners on 14 occasions, in French rugby's Clasico.
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