Lars Stindl opened scoring early for Germany after five minutes, with Tom Rogic equaling for Australia in the 40th minute, but then Julian Draxler gave the lead again to Germany just four minutes later from a penalty.
Leon Goretzka scored the third goal for Germany three minutes into the second half and then eight minutes later Tomi Juric scored a second goal for Australia, Efe news reported.
The German side managed to keep its lead and secure the first three points in the tournament.
With this win, Germany is in second position in Group B behind leader Chile, which defeated Cameroon 2-0 on Sunday.
Australia is in third place in the group ahead of Cameroon, as both teams have no points.
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