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.
As part of the build-up to next month's Cardiff 2014 Heineken Cup and Amlin Challenge Cup finals weekend, ERC has joined forces with the WRU, Cardiff Blues and adidas to develop an annual grassroots community rugby programme targeting young players.
The Ulster Rugby full back, Jared Payne (No 15), has been suspended for two (2) weeks following an independent Disciplinary Hearing in Dublin arising from the Heineken Cup quarter-final match against Saracens at Ravenhill Stadium on Saturday, 5 April.