Two-time BMW Open defending champion Holger Rune was stunned by home hope Jan-Lennard Struff in Munich on Saturday and won’t bid for a third consecutive title. Struff earned the biggest win of his season as he downed Rune 6-2, 6-0 to reach the final in Munich for the second time. “It was the perfect match. Of course I’m going to try to win the title now. I will give it my all,” the German said. Struff is seeking his maiden tour-level title. Earlier in the day completed a 7-5, 6-4 victory over Canadian Felix Auger-Aliassime, after that match was stopped due to darkness the previous day with Str…