Auch became the fifteenth team to win a European title as they stunned Worcester Warriors with a 20-point first-half burst to win the European Shield.
It was the third year in a row the Shield has gone to a French side and Auch followed in the footsteps of Castes and Montpellier in taking the crown at the Kassam Stadium.
With the wind at their backs Auch attacked from the start and a brilliant counter attack launched by outside half Yannick Lafforgue paved the way for right wing Raphael Bastide to raced 40 metres to score.
Fullback Jean Baptise Dambille added the conversion and ended the first half with 10 points. Worcester outside half Tommy Hayes kicked a penalty after seven minutes, but it was all one-way traffic after that, with Auch number 8 Gregory Patat corssing form a close range lineout and Dambille adding the conversion and two penalties.
The fullback kicked a third penalty midway through the second half to stretch the French club's lead to 20 points.
Although Worcester staged a late rally in which skipper Darren O'Leary grabbed a try, which Hayes converted it, was too little too late.