African champions Cameroon on Sunday crashed out of the FIFA Confederations Cup in Russian Federation.
Germany was leading through Kerem Demirbay's 48th-minute strike when a case of mistaken identity halfway through the second half that replays were meant to eradicate left the African champions bemused and irritated.
The drama came on a landmark day for Joachim Low, who was able to celebrate his 100th win as Germany's head coach in his 150th game in charge.
Any chance of an unlikely comeback from Cameroon was ended three minutes later when Werner restored Germany's two-goal lead with his second of the match.
It was only after Cameroon's players insisted he review the incident again that he realised his error, rescinded Siani's sending off and instead flashed the red card to the correct culprit Mabouka.
Australia, meanwhile, are out and finish third in the group as their winless Confederations Cup run extends to six matches despite a creditable performance against the world's fourth-ranked side.
The Africa Cup of Nations holders were 1-0 down to the world champions thanks to Kerem Demirbay's spectacular maiden worldwide goal early in the second half, when Mabouka caught Emre Can with a high studs-up challenge.
GERMANY eased their way to a semi-final date with Mexico in the Confederations Cup.
They paid for those misses when Rodriguez turned the ball in from Eduardo Vargas' header after the Australia defender failed to clear an attack.
The Indomitable Lions will now turn their attention to the World Cup qualifiers where they confront the Super Eagles of Nigeria in a double-header and hope to qualify from a "group of death" that also include Algeria and Zambia.