Top seed Dominic Thiem fought back from a set down to reach the final in the men’s draw – and also book his place at the season-ending ATP Finals.
The Austrian will play Stefanos Tsitsipas after beating Russia’s Karen Khachanov 2-6, 7-6 (7/5), 7-5 in two hours and 41 minutes.
The 21-year-old Tsitsipas triumphed 7-6 (8/6), 6-4 in a battle of the rising stars against 22-year-old Alexander Zverev.
Thiem, who has now reached the ATP Finals for a fourth time in a row, said: “For me personally, it was one big goal when I started into the season, I’m very, very happy that I made it (the London Finals) again.
“But it’s not because of today’s win, it’s because of all the season.”
Thiem, ranked fifth in the world, beat former number one Andy Murray on Friday and is one victory away from a 15th career title.
Also already qualified for London are Novak Djokovic, Rafael Nadal, Roger Federer and Daniil Medvedev.