Australia's Alex De Minaur backed up his upset of Novak Djokovic by defeating Alexander Zverev Saturday, but it was not enough to prevent Germany booking a United Cup final against Poland. De Minaur battled past the world number seven 5-7, 6-3, 6-4 to send the tie to a deciding mixed doubles after Angelique Kerber dug deep to beat Ajla Tomljanovic 4-6, 6-2, 7-6 (9/7). But Zverev made amends, partnering Laura Siegemund to claw past Storm Hunter and Matt Ebdon 7-6 (7/2), 6-7 (2/7), 15-13 in a see-sawing match which finished at 2:18am and saw them save four match points.