Australias Alex de Minaur has survived four match points to beat fellow young gun Andrey Rublev and reach his first ATP Tour 500-level final in Washington DC.
The 19-year-old Australian fought back from a set down against Russian 16th seed Rublev to prevail 5-7, 7-6 (8-6), 6-4 in a high-quality Citi Open semi-final.
His reward is a clash with defending champion and world No.3 Alexander Zverev in Sundays final.
It will be de Minaurs second appearance in an ATP Tour final, having reached the decider at the lower-tier Sydney tournament in January.
It continues a dramatic rise for de Minaur in 2018.
He started the year ranked No.208 but he is set to crack the top 50 for the first time when rankings are updated on Monday and he will go to No.33 if he beats Zverev.
All four semi-finalists at the Citi Open – Zverev, de Minaur, Rublev and Greeces Stefanos Tsitsipas – were 21 or younger. It is the first time four players of that age have reached the semi-finals of an ATP World Tour event since Buenos Aires in 1995.
While 20-year-old Rublev fell just short of reaching his first final at 500 level, he was competing in just his third tournament since a three-month hiatus due to a stress fracture in his lower back.
He was seeking a second ATP World Tour title, after claiming victory last year in Umag as a lucky loser.