Great Britain’s Katie Swan lost in three sets to Ysaline Bonaventure as GB fell 1-0 behind to Belgium in their Fed Cup promotion play-off.
World number 524 Swan, 16, was beaten 6-3 3-6 6-3 by the 21-year-old, ranked 160, in the opening rubber of the best-of-three tie in Eilat, Israel.
British number two Heather Watson plays Alison van Uytvanck later before a potentially decisive doubles rubber.
GB beat South Africa and Georgia this week to reach the Group 1 play-off.
Victory against Belgium would see Judy Murray’s side progress to a World Group II play-off in April, and the possibility of a first home tie for Britain’s women since 1993.