Fed Cup 2016: Christina McHale and Madison Keys starred for the USA in Brisbane

The United States have a commanding 2-0 lead over Australia after day one of their Fed Cup World Group play-off in Brisbane.

Christina McHale and Madison Keys won the opening singles rubbers, meaning the Americans need to win just one of Sunday's three matches to secure a place in the World Group for 2017.

Keys defeated Daria Gavrilova 6-4 6-2 to get the USA off to a perfect start and McHale then came from a set down to defeat Samantha Stosur 3-6 6-1 7-5.

McHale was a surprise selection to play the second rubber ahead of the higher-ranked Coco Vandeweghe but, having lost the first set, she dominated the start of the second, winning 17 of 18 points and 13 in a row, before going on to level the match in just 26 minutes.

Stosur 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.

The Aussie eventually dropped her serve at 5-5 and McHale calmly served out the match, clinching victory with a forehand down the line.

Earlier, Keys overpowered newly-qualified Australian Gavrilova, using her powerful forehand to full effect on the purpose-built clay court on Pat Rafter Arena.

Gavrilova was unable to cope with the forceful groundstrokes of Keys, who won in just 77 minutes to give the Americans an early advantage.

Despite the great start, US captain Mary Joe Fernandez is not celebrating yet.

"It's closer but it's nowhere near the finish line," she said. "It's not going to be easy. Every match is close, you can make a case for each team in every match."

Defeat would mean Australia will remain in World Group II but captain Alicia Molik is not giving up.

"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."