Emma Raducanu put together one of her best performances of the year to beat Slovakia's Viktoria Hruncakova in straight sets and put Britain on the brink of reaching the Billie Jean King Cup final.
The 22-year-old has already beaten Germany's Jule Niemeier and Canada's Rebecca Marino in straight sets in the competition in Malaga, and showed imperious form to race into a 5-1 lead in the opening set on Tuesday.
A wobble followed, with a double fault on break point scuppering her first attempt to serve out the set, but the 2021 US Open winner recovered to claim it 6-4 in front of a crowd dominated by Union Jacks.
The second set was a tighter affair from the outset, staying on serve until its fifth game where Raducanu sent down some brutal returns to seize the initiative.
A tense hold followed, but the Brit soon pressed home her advantage with another break and eventually claimed the contest 6-4, 6-4.
Britain were last in the final of the BJK Cup in 1981 and have finished as runners-up on four occasions, but have never won the competition formerly known as the Federation Cup.
Katie Boulter now takes on Rebecca Sramkova with a chance to seal a spot in Wednesday's final against Italy. Should Boulter lose, Heather Watson and Olivia Nicholls are slated to play in the deciding doubles match for the team captained by Anne Keothavong.