Emma Raducanu withstood a late surge from France's Diane Parry to secure Great Britain's place in the Billie Jean King Cup Finals.
Raducanu came from a set down to hold a 5-2 lead in the third set and had two match points on serve before being pegged back by an inspired Parry.
But Raducanu kept her nerve to win 4-6 6-1 7-6 (7-1) and give Britain an unassailable 3-1 lead in Le Portel.
This was a superb victory for Britain, who were facing a tough task away against a French team that mixed clay-court experience with youthful exuberance.