Nick Kyrgios says he will take confidence from his win over big-serving American John Isner in their most recent match when they attack the Davis Cup's pivotal second singles encounter at Pat Rafter Arena on Friday.
The victor of the quarter-final will face either Belgium or Italy in September's semi-finals.
Even Hewitt thought a win might be a bridge too far but his body language on the side of the court said it all as Thompson showed a clinical side when Sock began to lose energy and errors filtered in to his key weapon, a whipping forehand.
"I'm looking forward to getting back here and having some home support", said Kyrgios, who had to deal with a hostile crowd when he lost to Federer in Miami last week.
If Kyrgios can not finish the job it will fall to Jordan Thompson, who battles Isner in Sunday's second match.
The Americans named Sam Querrey and Steve Johnson for Saturday's doubles rubber against John Peers and Sam Groth.
Late in the first set of the doubles, former Australian Davis Cup victor Todd Woodbridge said on Channel Seven commentary that Sock looked as "flat as he was when he finished the match" on Friday.
Jack Sock and Steve Johnson battled past Sam Groth and John Peers to keep the US alive on Saturday in Brisbane.
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Kyrgios was superb against Isner.
Success allowed Sock to gain a measure of revenge on Thompson after his surprise singles defeat to the 22-year-old, and he told daviscup.com: "Jordan played great yesterday, he deserved to win, he was the better player".
It is the 47th Davis Cup meeting between the USA and Australia, the two most successful countries in the history of the competition - the US has won the title 32 times, Australia 28. "And I returned really well today so I'm really happy to get the win".
Sock looked out of sorts at times and served two double faults to hand Thompson his first break at 5-3.
"I'm super proud of these guys today, but it still will take a monstrous effort from us on Day 3", Courier said. "No matter who goes out there for us I'll be quietly confident that they're going to play well".
Lacking his opponent's court speed, Isner swung for the fences and scrapped to within two points of forcing another set, but two fierce returns off the Australian's racquet stole the momentum and set up Kyrgios for his match-winning 20th ace.
The American rallied to win the second set, then recovered from 4-1 down to level the third set before Thompson won it in a tiebreaker.