FRANKFURT, Germany — Steve Darcis defeated Alexander Zverev 2-6, 6-4, 6-4, 7-6 (8) to send Belgium into the Davis Cup World Group quarterfinals with an unsurmountable 3-1 lead over Germany on Sunday. With the tie already decided, Ruben Bemelmans beat Mischa Zverev 7-5, 6-1, giving Belgium a 4-1 upset victory — its first over Germany
