Minsk - CoCo Vandeweghe beat Belarus' Aliaksandra Sasnovich in straight sets on Saturday to give the visitors the United States the lead in their first Fed Cup final since 2010.
World's No 10 Vandeweghe won, 6-4, 6-4, in one hour 27 minutes her first ever meeting with the 23-year-old Sasnovich.
"That's my job, I'm top-ranked player in our team," Vandeweghe said on court after the match. "And you can see the result on the scoreboard."
"I started perfect both sets with early breaks but it wasn't easy to close out on both occasions as Aliaksandra was very motivated and played really well today."
Vandeweghe, this season's Australian Open and US Open semi-finalist, looked in command from the start on the hard court in the packed Minsk Chizhovka 8 000-seat arena peppering her opponent with shots from the baseline.
The 25-year-old American started the rubber with an immediate break clinching a 2-0 lead, which she confidently kept to take the opening set in 45 minutes.
The players traded breaks early in the second set but Vandeweghe, playing with slightly more accuracy, went 3-1 up.
Sasnovich, ranked 87th in the world, fought back and pulled the scores level at 4-4. Vandeweghe responded by breaking again in the ninth game and then held her serve to win the set and the match.
The match between Belarus' Aryna Sabalenka and Sloane Stephens of USA continues Saturday's schedule.