Alexander Zverev stayed on course to successfully defend his BMW Open title by defeating Chung Hyeon to set up an all-German final against Philipp Kohlschreiber in Munich.
The top seed lost the first three games against his fellow young gun but recovered to win 7-5 6-2.
Zverev was guaranteed to face a countryman, with Kohlschreiber taking on Maximilian Marterer, and it was the three-time former champion who prevailed 6-2 6-4.
Joao Sousa became the first home finalist at the Millennium Estoril Open, beating Barcelona runner-up Stefanos Tsitsipas 6-4 1-6 7-6 (7/4).
In the final the in-form Portuguese, who had lost his first match on his three previous appearances, will play young American Frances Tiafoe after he stunned defending champion Pablo Carreno Busta 6-2 6-3.
There will be a first-time winner on the ATP Tour at the Istanbul Cup, where Tunisia's Malek Jaziri will take on Taro Daniel of Japan.
Neither man has ever reached a final before but will clash on Sunday after Jaziri defeated Laslo Djere 6-3 6-2 and Daniel saw off France's Jeremy Chardy 6-3 4-6 6-4.