Teenager Katie Swan upset world number 327 Ekaterine Gorgodze to give Great Britain an early lead over Georgia in their crucial Fed Cup tie.
Swan, Britain's youngest ever Fed Cup player at 16 years old, won 6-3 6-3 in the opening contest of the best-of-three tie in Eilat, Israel.
Heather Watson can seal victory in the second singles and ensure Britain top their pool in Europe/Africa Group 1.
That would see Britain progress to Saturday's final qualifying round.
Captain Judy Murray brought Swan into the side after Australian Open semi-finalist and British number one Johanna Konta withdrew because of illness.