BRISBANE (AFP) - Christina McHale and Madison Keys won the opening singles rubbers, to give the United States a commanding 2-0 lead in their Fed Cup World Group play-off tennis tie against Australia on Saturday.
After Keys beat Daria Gavrilova 6-4, 6-2 in the opening tie, McHale came from a set down to upset Australian No. 1 Samantha Stosur 3-6, 6-1, 7-5.
The US needs to win only one of Sunday's three matches to book their place in the World Group in 2017, while a loss for Australia would see them remain in World Group II.
US captain Mary Joe Fernandez said the Americans wouldn't take anything for granted heading into Sunday's matches.
"It's not going to be easy - every match is close, you can make a case for each team in every match," Fernandez said.
"That's why you have to go out there and give it your all and get that next win.
"It's closer but it's nowhere near the finish line," she added.
Stosur had looked certain to level the tie when she took the first set against McHale, who was a surprise pick to play the singles ahead of higher-ranked Coco Vandeweghe.
But the Australian imploded at the start of the second set, losing 17 of 18 points, and 13 in a row, to surrender the set in just 26 minutes.
"It was a pretty bad start (to the set) and that kind of gave her all the momentum from that point on," said Stosur.
"From four-love down I knew it was a long way back."
She regained her composure and the third set was much closer, but the steadier McHale always appeared to have the edge over the former US Open champion, who hit a total of 44 unforced errors.
Stosur battled hard, but she eventually dropped her serve at 5-5 and McHale calmly served out the match, clinching victory with a forehand down the line.
The American said she and Stosur had similar styles of play with both favouring big forehand ground strokes.
"We were both trying to do the same things to each other," said McHale.
"She was doing it better than me in the first part of the match but then I was able to run around my forehand as the match went on."
Earlier, Keys overpowered newly qualified Australian Gavrilova, using her booming forehand to full effect on the purpose-built clay court on Pat Rafter Arena.
The pint-sized Gavrilova was unable to cope with the brute force of Keys, who won in 77 minutes to give the Americans an early advantage.
"It was pretty good start for what is hopefully a successful weekend," said Keys.
"Dasha (Gavrilova) is very good at getting a lot of balls back so I think I was pretty good at not going for it too early and just waiting for my shots."
Australia captain Alicia Molik said she remained confident of the home team coming back to win the tie.
"No question we'd prefer to be at one-all at worst but it is what it is," she said. "It's about regrouping and trusting ourselves."