Nick Kyrgios and Alex de Minaur combined to guide Australia into the ATP Cup semi-finals after winning a nail-biting doubles match against Great Britain on Thursday.
After the singles ties were shared - Nick Kyrgios thrashing Cameron Norrie 6-2, 6-2 before Dan Evans levelled with a thrilling 7-6, 6-4, 7-6 win over De Minaur - Australia captain Lleyton Hewitt made a bold, late call to drop doubles pair John Peers and Chris Guccione in favour of Kyrgios and de Minaur.
It was a decision that ultimately paid off after the home team clinched the tie with an 18-16 third-set tiebreaker in front of a raucous Sydney crowd.
However, it didn't appear to be heading that way after the British pair of Jamie Murray and Joe Salisbury recovered from an early break to take the first set 6-3. But spurred by Kyrgios' booming serve, Australia took the next 6-3 before a marathon tiebreaker that lasted more than half-an-hour.
Murray and Salisbury had four match points, which were all saved, with Australia finally converting on their fifth match point, sparking jubilant scenes.
Australia await the winner's of Friday's quarter-final between Spain and Belgium.
"That was incredible tennis. All three matches today everyone gave 100 percent and left it all out on the court," Hewitt said.
"Really proud of the boys, the way they were able to turn it around... it could have gone either way."
The tie was notable for Evans' clash with world No 18 De Minaur, a three-hour 23-minute contest that is a contender for match of the tournament.
After Evans took the opening set in a tense tiebreaker, De Minaur fought back to grab the second.
He went 4-2 behind in a see-sawing third but rallied again as they exchanged service breaks with the Australian showing nerves of steel to save four match points and take it to another tiebreak, which the exhausted Briton finally won
"That's about as good as I've got really and I only got through by the skin of my teeth," said Evans, ranked No 42.
"I sneaked it and this is what team competition is always about, particularly Britain and Australia, it's always a great rivalry and there's been great spirit."
A composed Kyrgios beat world No 6 Stefanos Tsitsipas on Tuesday and carried that momentum into his clash against Norrie.
The mercurial Australian has been a model of concentration and focus at the ATP Cup as he thrives in the team environment.
It is partly due to having a six-month suspended ban hanging over him, imposed in September for calling an Irish umpire a "potato" and a "tool" in Cincinnati. He also accused the ATP of being corrupt before backtracking on the allegation.
"We've got each others' backs. I love the team event. Rusty [Hewitt] is the best captain, the teammates have been supporting each other, being there for each other and that's paid off," Kyrgios said.
Kyrgios' flamboyance and natural talent shone brightly against an error-riddled Norrie. He played some glorious drop shots, served beautifully and exhibited his rocket-like forehand in front of a vocal crowd at Ken Rosewall Arena.
Argentina face Russia in the second quarter-final later Thursday.
