Belarus drew level with the United States in the Fed Cup final after Aryna Sabalenka beat Sloane Stephens 6-3 3-6 6-4 in front of a home crowd in Minsk.
US Open champion Stephens, ranked 13th in the world, fought back from one set down to set up an entertaining decider.
Sabalenka, 19, had to break back twice in the third set on her way to victory.
The world number 78 leads the campaign for Belarus after twice Grand Slam champion Victoria Azarenka withdrew because of a custody battle.
Belarus, who are competing in the final for the first time, were 1-0 down after Coco Vandeweghe beat Aliaksandra Sasnovich 6-4 6-4 in the first singles match.
They are now level on 1-1 with the United States, who are without Serena and Venus Williams as they chase a record 18th Fed Cup title.
Sabalenka will face world number 10 Vandeweghe next, while Stephens will look to bounce back against Sasnovich, ranked 87th in the world.
Should the tie go to a deciding fifth rubber, American 2016 French Open quarter-finalist Shelby Rogers and January’s Shenzhen Open runner-up Alison Riske will take on Belarus duo Vera Lapko and Lidziya Marozava in doubles.