Pat Eddery produced a fine ride to land the Group One Prix Ganay on the John Dunlop trained Golden Snake at Longchamp yesterday.
Front-running tactics used to draw the sting out of Egyptband, the 11 to 10 favourite, worked a treat.
Eddery jumped the 10 to 1 shot off in front, tracked by With the Flow and the second British challenger Little Rock.
Turning into the straight Golden Snake had a clear lead and Eddery maintained the pressure all the way to the line. Egyptband, anchored towards the rear by Olivier Doleuze, made significant late headway but failed by three lengths to catch the winner.
With The Flow was another three lengths back in third just ahead of the Kieren Fallon-ridden Little Rock.
A delighted Dunlop remarked: "Pat rode a masterful race - remember he was riding Arc winners when Peslier and the rest were in short trousers.
"We thought the only way to win the Ganay was to go off in front. We didn't want to get involved in a French-type sprint finish with Egyptband."
The big disappointment of the race was last year's German Derby victor Samun, who beat only two home.
His trainer Andreas Schutz said: "That was his worst race so far. He had worked with a horse that had won a Group race already this season and went really well in that gallop. We will take him home and scope him to see if there's anything wrong."
This was Golden Snake's second win in Group One company in France and his fourth in total.
The next target for the son of Danzig is likely to be the Prince of Wales's Stakes at Royal Ascot.
Fallon had earlier finished second on Snataka in the Group Three Prix Vanteaux behind the Pascal Bary-trained Mare Nostrum.
Ad Hoc shrugged off a tough race just seven days ago to triumph in stunning fashion in the Whitbread Gold Cup at Sandown on Saturday. He stormed home by 19 lengths to clinch the owners' title for Robert Ogden on the final day of the jumps season.