The former England star’s fifth kick of the match in the 76th minute edged a tight contest in which Australian Matt Giteau scored two tries for the visitors.
Bernard Laporte's Toulon also won on the road last week in Perpignan and sat top of the table for a while before Biarritz’s 25-19 win in Agen later on Saturday put them at the summit.
Perpignan went down again on Friday, this time 26-22 away to Bordeaux.
Toulouse came from behind to beat minnows Mont-de-Marsan 37-22, Clermont lost 13-8 in Montpellier, Bayonne kicked their way to a 24-11 win at home to Stade Français and Castres were too strong for Grenoble, winning 30-13.
- Bernard Laporte