The highly anticipated USA v Switzerland tie came down to a live mixed doubles rubber after Serena Williams and Roger Federer each won their respective singles rubbers.
Federer gave Switzerland a 1-0 lead in the tie with a 6-4 6-1 win over Frances Tiafoe.
Williams then overcame a case of the first-set wobbles to post a 4-6 6-4 6-3 win over Belinda Bencic.
The mixed doubles encounter that now decides the winner of the tie marks the first time Federer and Williams have faced off against each other in a competitive match.
Williams raced out to a 3-0 lead in the opening set of her singles match, but Bencic won six of the next seven games to put the USA on the brink of elimination from the title race.
Team USA had already lost their opening tie to Greece, and were 1-0 down against Switzerland after Federer’s 57-minute win over Tiafoe.
But Williams lifted in the big moments, breaking Bencic in the final game of the second set to level the scores, before powering to victory in the third.
“It’s definitely a relief. She played really well,” Williams said.