Union Berlin came from behind to reach the German Cup semi-finals for a second time on Tuesday, 2-1 over second division St Pauli Hamburg who went down from two costly slip-ups. The visitors, who had ousted title holders Borussia Dortmund in the previous round, took the lead in the 21st minute when Daniel-Kofi Kyereh converted on a free-kick with a low shot with Union goalkeeper Frederik Rönnow not looking good. Union got the equalizer with the last play of the opening half. St Pauli goalkeeper Dennis Smarsch slipped while coming out of his goal, and Sheraldo Becker scored into the empty net. …