Barbora Krejcikova and Anastasia Pavlyuchenkova have re-written the tennis record books to set up the most unlikely final at the French Open.
Pavlyuchenkova broke the women's record for most appearances at grand slams before making a final on Thursday, beating Tamara Zidansek 7-5, 6-3 in the first semi.
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The Russian finally reached her first grand slam final at a record 52nd attempt, having previously made six quarter-finals but never going further.
She will play Krejcikova in Saturday's final after the Czech doused the fire of Maria Sakkari to become just the eighth unseeded woman ever to make the French Open singles final.
The seemingly nerveless Krejcikova had to overcome her own erratic form and save a match point before finally subduing the Greek favourite Sakkari 7-5 4-6 9-7 after three hours and 18 minutes.
In the thrilling conclusion to an 84-minute deciding set, Krejcikova faced a match point at 5-3 down, only to repel it with a driven backhand volley.
After that reprieve, both players began to play by far their best tennis of a match that featured an astonishing 111 unforced errors.
Krejcikova earned four match points of her own only to see Sakkari conjure up brilliance to save them all.
On her fourth match point at 8-7, Krejcikova felt she had won when Sakkari's shot, called out, was ruled to have hit the line. The Greek won the replayed point.
But World No.33 Krejcikova quickly earned match point number five, cracking her 31st winner to earn by far the biggest victory of a career that has seen five grand slam doubles titles but play in only five main draw singles.
"I always wanted to play a match like this, a challenging match where we're both playing so well," said Krejcikova.
"Even if I lost today, I'm very proud of myself. Fighting, in life, it's the most important thing."
Pavlyuchenkova breaks new ground to make French Open final
Earlier, 29-year-old Pavlyuchenkova became the first woman to reach her maiden final after playing more than 50 grand slams.
With all the players in the last four making their grand slam semi-final debuts, opportunity knocked for the unlikely quartet but Pavlyuchenkova, who had never previously been able to get past the quarter-final despite six attempts, was not about to miss out in her 52nd slam.
The 31st seed overcame a nervy start on a hot, humid day in which she went 2-0 down to gradually take control of the contest with her all-court solidity.
Zidansek, a 23-year-old former junior snowboard star who had never previously been past the second round of a grand slam, went for broke as she fired in 27 winners, many from her sweet forehand, but her inexperience told.
Pavlyuchenkova, who has cracked more winners than anyone in the women's draw, hammered 19 more to take her total to 174 but it was the higher error count from the erratic Zidansek which proved significant as she sprayed 32 wayward shots over one hour 34 minutes.
Pavlyuchenkova, who had begun to look as if she was struggling physically a little in the heat, kept targeting the Slovenian's backhand and looked in total command in the second set at 4-1 up, but a two double-fault game saw her gift an opportunity to her opponent.
She will be the first Russian woman to contest a slam final since Maria Sharapova lost to Serena Williams in the Australian Open in January 2015.
"It's been a long road. I had my own long special road," said Pavlyuchenkova, who made her grand slam debut at Wimbledon in 2007.
"Everybody has different ways. I'm just happy I'm in the final."
The tennis world was left in awe over the extraordinary scenes at Roland Garros on Thursday.
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