The United States survived a cliff-hanger of a match at the Hopman Cup in Perth, where they snatched victory from the jaws of defeat against France who were edged out 2-1.
USA were seemingly heading towards defeat when John Isner lost his singles rubber to Jo-Wilfried Tsonga, and then Venus Williams trailed by a set and a break in match No.2.
But from 1-4 down in the second set, the 32-year-old American won six of the next seven games before securing the only break of the decider in the seventh against Mathilde Johansson.
In the end, Williams posted a 3-6 7-5 6-4 victory in two hours and 21 minutes.
The US pair also had to recover from a set down in the mixed doubles decider, edging out Tsonga and Johansson 6-7 (5-7) 6-2 10-8.
The victory is the USA's second in Group B and they now face Spain in a contest that will probably decide which team progresses to the final later this week.
In their first match against South Africa on Sunday, the US were also forced to recover from the loss of the opening tie, when Venus once again won her singles after conceding the first set.