Unseeded Czech Marketa Vondrousova became the first teenager to reach a Grand Slam final for 10 years as she beat Johanna Konta 7-5 7-6(2) at the French Open on Friday.
The 19-year-old lost the first 10 points of the match on a rainy Court Simonne Mathieu but the left-hander had more guile than her more powerful opponent in testing conditions.
She will take on Australia`s Ashleigh Barty in Saturday`s final after she prevented an all-teenager final by beating American Amanda Anisimova in three sets.
Vondrousova will hope to go one stage further than Ana Ivanovic in 2007, the last teenager to reach the Roland Garros final, when she lost to Justine Henin.
Konta, bidding to become the first British woman to reach a Grand Slam final since 1977, will be kicking herself after squandering leads in both sets.
The 28-year-old, who had never won a round at Roland Garros before this year, had three set points when she led 5-3 in the opener, but on first lashed an easy volley well over the baseline with the court at her mercy.
From that point on Vondrousova began to use her splendid array of drop shots, lobs and superb anticipation to take charge, helped by regular errors off the Konta racket.
She broke the Konta serve to level at 5-5 and then held with an exquisite drop shot and lob volley combination.
Vondrousova claimed the first set with a defensive lob that landed plumb on the baseline.
The Czech, whose tattoo says "no rain no flowers" -- an appropriate message considering the conditions and the court`s setting, surrounded by greenhouses -- lost focus at the start of the second set as Konta moved 3-1 ahead.
Konta consolidated her lead to 5-3 but again the wheels came off as her game began to disintegrate.
Serving for the set she lost a volleying exchange at 15-30 and then double-faulted at 30-40.
Konta bashed away a forehand winner to take the set into a tiebreak but Vondrousova showed remarkable calm to move 6-2 ahead and then clinch victory with a disguised dropshot.
Vondrousova, who has won more matches then any other player on the WTA Tour since the Australian Open, will become the first Czech to win the French Open since Hana Mandlikova in 1981 if she overcomes fellow Grand Slam final debutant Barty on Saturday.