Jason Kubler's come-from-behind 6-3 7-6 (7-3) defeat of highly fancied Dan Evans was the highlight for the hosts, who lost their first three matches in straight sets to concede defeat in the tie with two matches in hand.
Alex de Minaur, Zoe Hives and Maddison Inglis were all outplayed after a disruptive lead-in to the tournament at Sydney's Ken Rosewall Arena.Â
De Minaur was promoted to Thursday's top-seeded men's match-up after Nick Kyrgios pulled out with an ankle injury and Inglis was rushed in only hours before Friday's match when Ajla Tomljanovic went down with a knee complaint.
Tomljanovic's injury is not expected to affect her Australian Open chances and Tennis Australia officials remain hopeful she can line up against Spain's Paula Badosa on Tuesday.
Replacing the world No.33 was a tough ask for No.180 Inglis, who had not been expecting to play in the United Cup at all and was bed-ridden with a stomach bug as recently as Wednesday.
Inglis needed to defeat world No.98 Harriet Dart on Friday evening to give Australia any hope of salvaging the tie but dropped the first set after errors began creeping into her game and eventually fell 6-4 6-4.
Dart's backhand was a handful for Inglis but the momentum finally shifted to the local when she broke her rival for the first time midway through the second set.
Two double faults from Inglis in the same game gave Dart the chance to serve for the tie, though, and the precise Brit made no mistake.
"I feel like I gave it everything I could, just a few cheap errors here and there which I think come normally in your first match of the season," said Inglis, who had never previously represented Australia.
"But I really enjoyed it."
Australia's sixth-best male player on ranking, world No.107 Kubler punched well above his weight to score an early break over Evans and take the first set but was brought back to earth by the world No.27 in the second.
Evans, who had defeated Kubler in both previous meetings, looked primed to go on with the match up 5-0 in the second set but the plucky Australian refused to lie down.
Kubler was the first Australian to truly weaponise the crowd and broke back twice on his way to levelling the scores at 5-5, before winning on tie-break to the delight of the locals.
"At 5-0 we were saying to give him some different looks. Try and move some things," Kubler said.
"That's sort of where our mindset was and if anything that sort of helped me play a bit more proactive instead of a bit more reactional."
Playing captain Sam Stosur and doubles specialist John Peers were the only Australians to go into their match as favourites and accounted for Dart and Jonny O'Mara in the mixed doubles 7-6 (7-4) 6-4 after Evans withdrew late.
After claiming the first set on tie-break, the Australians broke the Brits late in the second set and served out for the win.
Despite the loss in the tie, Australia is still able to advance to the next stage of the tournament but must hope Spain beats Great Britain in the tie that begins on Saturday.
After that, Australia needs to beat Spain by a bigger margin than either of the other two ties in their group.
