Ashleigh Barty was unable to cap her hugely successful season with a Fed Cup victory after France edged Australia 3-2 after the final went down to the deciding doubles on Sunday.
Barty, who ended the WTA Tour year as the world No 1, French Open champion and WTA Finals winner, partnered with Samantha Stosur in the doubles against Kristina Mladenovic and Caroline Garcia, with the French team claiming a 6-4, 6-3 win at Perth Arena.
It was France's third title and first since they beat the United States 16 years ago, piling more misery on seven-time champions Australia who have now lost all nine of the last Fed Cup finals they have appeared in.
Mladenovic and Garcia, who won the 2016 French Open doubles title, bounced back from going an early break down in the first set to expose Stosur's weaknesses, with the veteran out-of-sorts and making too many mistakes.
Barty, stunned by Mladenovic in a singles rubber earlier in the day, did her best to keep Australia in the hunt, but the French pair were clinical, racing to victory as their teammates went wild.
"I'm the proudest man on the planet right now, I'm so proud of my girls and my team. They deserve it because they fought for a long time for this title," France captain Julien Benneteau said courtside.
The final marked the last Fed Cup played under the current format, with an overhaul next year seeing 12 nations compete in a six-day event in Budapest.
That will mean an end to home ties and the atmosphere they bring, with the 26,951 fans turning up over two days in Perth the second-highest Fed Cup attendance on record after Roland Garros (30,000) in 2005.
The doubles clash was set up by Ajla Tomljanovic hauling the home team back into the tie by beating France's Pauline Parmentier 6-4, 7-5. She came on court after 40th-ranked Mladenovic upset Barty 2-6, 6-4, 7-6.
Croatian-born Tomljanovic, in her Fed Cup debut for Australia, had been thrashed 6-1, 6-1 by Mladenovic in the opening singles rubber on Saturday. But captain Alica Molik kept faith with her and she bounced back to beat Parmentier 6-4, 7-5.
"Really glad I got a second chance today and got the win and kept us in," Tomljanovic said. "The team has been unbelievable all week and it is such a privilege to play for you guys."
Earlier Barty, who has been in scintillating form, shutting out Garcia 6-0, 6-0 on Saturday, crashed in a classic.
"From my point of view I fought as hard as I could and I hope that I did my team proud and all Australians proud. I fought with everything I had left," said Barty.
Barty started where she left off after the "double bagel" of Garcia on Saturday, breaking Mladenovic's first service game with a net volley to extend her streak to 15 games this weekend.
But Mladenovic held serve to end the Barty run and it became a closer affair before the Australian began forcing errors to take the first set.
Barty saved five break points in the opening game of the second set, but Mladenovic finally worked a first crucial break with some quality passing shots, with a forehand long from Barty giving her a 5-4 lead. She held her nerve to serve out the set.
Mladenovic, who beat Barty on clay in Rome earlier this year, was on a roll with the French star breaking then holding for a 3-1 third-set lead.
Barty rallied for 3-3 but the errors again crept in and the set ultimately went to a tense tie breaker where Mladenovic triumphed.
"I just kept believing because I felt I was out there fighting and giving her a hard battle. I'm just so proud how I kept pushing and obviously won the game," Mladenovic said.