USA pair Steve Johnson and Jack Sock kept the Davis Cup quarter-final against Australia alive with a gritty five-set win over John Peers and Sam Groth in Brisbane on Saturday.
The winners of the tie will face either Serbia or Spain in the semi-finals.
The 21-year-old rebounded from mini-breaks in both tie breakers and managed to find a way to return two booming serves as he dug himself out of trouble to win 7-5 7-6 (5) 7-6 (5).
The Americans had needed the victory to remain in the quarter-final tie after Jordan Thompson stunned Sock 6-3 3-6 7-6 (4) 6-4 and Nick Kyrgios eased past John Isner 7-5 7-6 (5) 7-6 (5) in the opening singles on Friday.
The 79th-ranked Thompson won both of his singles in his Davis Cup debut against the Czech Republic in February, but he was more impressive against No. 15 Sock, the highest-ranked player in the quarterfinal.
Australia are seeking revenge after losing t o the U.S. in the first round past year and would progress to the semi-finals for only the second time since 2006 if Sam Groth and John Peers can wrap things up against Steve Johnson and Sam Querrey on Saturday.
The Americans can change on Sunday morning their nominated singles players and Sam Querrey has a last-start win to his credit over Kyrgios, last month in Mexico. "I don't know. He played a good match so deserved to win".
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However, two-time reigning MVP Stephen Curry is listed as doubtful to face the Pelicans on Saturday because of a bruised knee. To be away was different and tough but I looked at the big picture. "I knew it would get there at some point".
Thompson, 22 and from Sydney, couldn't help but remind fans of his captain, Lleyton Hewitt, as he scrapped and clawed through four sets against Sock, who lost 6-3 3-6 7-6 (4) 6-4 in a disappointing result for United States of America captain Jim Courier.
"I've been playing great tennis".
Hewitt said it was no surprise Sock - the highest-ranked player in the tie - was subbed into the doubles after United States captain Jim Courier had telegraphed the possibility of a late change.
There could be no excuse for three lazy points played by Sock when he lost serve at 2-2 in the fourth set, giving even more confidence to his lower-ranked opponent.
"Just playing within myself, not trying to go too big".
In the fifth set, the Americans broke Peers' serve to love and outplayed the Australians to clinch the match.
Super-fit Sydneysider Thompson, given an opportunity by Hewitt through the unavailability of Bernard Tomic, ran down a tiring Sock in just over three hours to post a 6-3 3-6 7-6 (7-4) 6-4 win at Pat Rafter Arena.