Sale Sharks seized control of Pool 1 thanks to a blistering first-half performance at English rivals Worcester Warriors.
Inspired by fly-half Danny Cipriani behind a dominant pack, Sharks hit the Warriors for three tries at Sixways before No8 Mark Easter secured maximum points in the 26-10 win.
That result severely dented Worcester's hopes of qualifying having been denied victory in the opening round by a late penalty at Oyonnax.
Sale are now four points clear at the top of the pool though will be well aware of the threat still posed by seasoned European campaigners Biarritz Olympique.
A potentially crucial bonus-point victory away from home will fill Stave Diamond's team with confidence for their back-to-back games against Oyonnax, who remain one of only two teams yet to score a try in the Amlin Challenge Cup this season.
Biarritz picked up their first win of the campaign against Oyonnax thanks to the power of their forwards who scored all four tries.
Pelu Table, Joshua Furno, Seremaia Burotu and replacement prop Eugene Van Stade all crossed in the 26-6 win at Parc des Sports Aguilera that catapults the Basque club back into contention.
Biarritz, led by Dimitri Yachvili, will want to continue their impressive European rugby heritage having qualified for the knock-out stages of either competition ten times in the past 13 years.
The directors of ERC voted unanimously at a Board meeting to postpone all decisions including the release of further instalments of ERC's distributable central revenues to the six shareholder countries until 19 February next when the Board will meet again to reconsider the issue.