In a lengthy semi-final that eventually finished well past 2 a.m. local time, Germany's mixed doubles duo of Alexander Zverev and Laura Siegemund got the better of Matthew Ebden and Storm Hunter in the decider after the teams split the singles.
Angelique Kerber had given Germany the lead when she beat Ajla Tomljanovic but Australia struck back when Alex de Minaur, roared on by the home support, came from behind to defeat Zverev 5-7, 6-3, 6-4.
Zverev had only 25 minutes between the singles and doubles matches but that did not stop him and he partnered Siegemund to beat the Australian pair 7-6(2), 6-7(2), 15-13 in a contest where both sides saved several match points.
"After the singles match it was obviously disappointing but I thought the level of the match was extremely high," said an exhausted Zverev, who was visibly cramping up after a total of five hours on court.
"We were still in the tie and we still had a chance to win it and I'm happy that we did that today."
Kerber had recovered from a set down and saved two match points to beat Ajla Tomljanovic 4-6, 6-2, 7-6(7) for her first singles win since her 18-month maternity break.
"I just tried to play as many matches as possible before going to Melbourne. I tried to learn from my last three matches," Kerber said.
"Coming out here and winning such a tough battle means a lot to me. It means a lot to have a match like this before going to the Australian Open."
The Australian Open runs from January 14th to 28th.
POLAND ADVANCE
Earlier, world number nine Hubert Hurkacz staved off a late comeback attempt by Adrian Mannarino and prevailed 6-3, 7-5, handing top seeds Poland a 1-0 lead in the $10 million tournament, which began last week with 18 countries in contention.
Iga Swiatek endured a more challenging outing against Caroline Garcia, as the world number one dropped the opening set before rediscovering her top level and winning 4-6, 6-1, 6-1.
An early double break in the decider put Swiatek ahead 4-0 and the 22-year-old never looked back from there as she claimed her fourth straight singles win of the season ahead of this month's Australian Open.
"I'm happy that I came back and I didn't make so many mistakes as in the first set," Swiatek said. "For sure, Caro was putting pressure as usual, so I'm happy that we're through to the final.
"Hubi played a great match today. He had everything under control, and it was nice watching that. For sure it made it a little bit easier for me."
Katarzyna Kawa and Jan Zielinski completed the sweep by beating Elixane Lechemia and Edouard Roger-Vasselin 6-3, 6-3.
