The German No.1, attempting to win his first title of the year, proved to be too strong for his Korean opponent and he will challenge compatriot, Philipp Kohlschreiber, for the trophy.

Kohlschreiber, who prevailed in Bavaria in 2007, 2012 and 2016, eased into the championship match with a 6-2 6-4 success over Maximilian Marterer. The veteran will be optimistic heading into Sunday’s showdown as he has edged two of his three previous meetings with his youthful rival.

“It was good,” said Zverev as he reflected on his semi-final win. “Obviously didn't start off well, from the 0-3 deficit. Played a pretty good match and the tactics I had for the match worked well.

“It’s going to be a tough match [the final]. Philipp has been in multiple finals here, won the title multiple times as well, so it’s not going to be easy.”

Taro Daniel generated headlines when he stunned Novak Djokovic in Indian Wells in March, and he has continued on an upward curve since his heroics in the California desert.

The industrious Japanese defeated Jeremy Chardy 6-3 4-6, 6-4 to reach his first ever final at the Istanbul Cup. He will tackle Malek Jaziri, who defeated Laslo Đere 6-3 6-2, in the biggest match of his career.

At the Estoril Open, Joao Sousa thrilled the locals by outlasting Stefanos Tsitsipas 6-4 1-6 7-6(4) to ensure home interest in Sunday’s final. Standing between the Portuguese and a third career title is Frances Tiafoe.

The charismatic American registered a big victory as he took out Pablo Carreno Busta, a quarter-finalist at Roland Garros last year, 6-2 6-3.