Berrahri took a significant step forward from last weekend's third at the unique St Moritz snow course to triumph for trainer John Best in the Grosser Preis Longines.
The eight-year-old, now a four-time winner at the iconic Swiss track, had finished more than 30 lengths behind the Paul Webber-trained New Agenda a week ago, but improved notably in the 1m1f conditions race on Sunday, plugging on gamely under Dennis Schiergen having duelled for the lead throughout.
Berrahri and fellow front-runner Samurai had been gifted a sizeable early lead, and it was Berrahri who looked in trouble in the back straight.
However, the son of Bahri stayed on gallantly as the petrol tank of Samurai quickly emptied entering the home straight.
The more patiently ridden duo of Fiesta and Sleeping Giant closed sharply inside the final furlong, but Best's runner had enough to hold on for victory.
He said: "The track was still riding slow with the temperatures not as cold as we had hoped.
"He was taken on for the lead early and looked beaten going down the back, but he battled back to regain the lead and held on bravely to win. He now heads for the Grand Prix next weekend."