Gloucester closed the gap on Pool five leaders La Rochelle with a hard-fought 13-6 victory to put their Amlin Challenge Cup hopes back on track.
James Simpson-Daniel crossed for the only try of a scrappy affair on 25 minutes in freezing conditions on the west coast of France.
The result leaves Bryan Redpath's men just one point behind their rivals at the top of the table.
Benjamin Dambielle slotted La Rochelle's points, with Nicky Robinson kicking a conversion and Freddie Burns two penalties to make up Gloucester's score.
For La Rochelle:
Pens: Burns 2
USA winger Kevin Swyrin scored a brace as Agen ran out 33-10 comfortable winners over Rovigo in Pool Five.
Swyrin opened and finished the scoring for the visitors who claimed maximum points in northern Italy. The Top 14 outfit also scored a penalty try as well as Osea Kolinisau's second-half effort.
Petrarca clinched their first victory in the competition with a 37-10 success over Spanish side Cetransa El Salvador in Pool Two.
Tries:Swiryn 2, penalty, Monribot, Kolinisau
Cons: Barnard 4