Timo Werner netted twice as Germany set up a Confederations Cup semi-final against Mexico with a 3-1 win on Sunday against 10-man Cameroon, who initially had the wrong player sent off. Germany midfielder Kerem Demirbay opened the scoring just after the break before Werner struck either side of Vincent Aboubakar's consolation effort for Cameroon on 78 minutes. But the video assistant referee system was again thrust into the spotlight when Cameroon defender Ernest Mabouka was sent off just past the hour for a dangerous tackle on Liverpool's Emre Can.
Colombian referee Wilmar Roldan initially sent off Sebastien Siani by mistake, before the decision was rectified and Mabouka was dismissed instead.
"I didn't understand it and I still don't understand it now," fumed Cameroon's Belgian coach Hugo Broos.
"I think this is something for the referee, he and he alone can explain what happened."
The victory in Sochi meant Germany finished top of Group B ahead of Chile, who drew 1-1 with Australia in Moscow.
The Germans face Group A runners-up Mexico in Sochi next Thursday in their semi-final, while Chile will face Portugal on Wednesday in Kazan.
Joachim Loew reached the milestone of 100 wins in his 150th international as Germany's head coach.
He maintained his impressive record of steering the national team to the semi-finals of every tournament over the last decade.
"I have to say I am very proud and full of praise for the team for reaching the semi-finals," said Loew. "We didn't necessarily expect this in the build-up from such a young team. The lads have done a good job."
Loew made four changes from the side which drew 1-1 with Chile on Thursday.
- Demirbay rocket -
Centre-back Antonio Ruediger came in for Arsenal's Shkodran Mustafi and Werner, the top-scoring German in the Bundesliga last season, took Lars Stindl's place up front.
After a strong season with Hoffenheim, Demirbay slotted into attacking midfield alongside captain Julian Draxler and Hertha Berlin's Marvin Plattenhardt, who came in for Jonas Hector on the left wing.
Cameroon fielded the same team for the third game in a row as midfielder Arnaud Djoum kept his place after Georges Mandjeck injured himself in the warm-up.
The first half was a poor reflection on both teams and was blighted by stray passes, an absence of precision and a lack of tempo.
But the world champions broke the deadlock when Draxler exchanged passes with Demirbay, who blasted past Cameroon goalkeeper Fabrice Ondoa from distance on 48 minutes.
Aboubakar and substitute Moumi Ngamaleu then sighted the Germany goal, but the African champions were reduced to 10 men when Mabouka raked his studs down Can's knee.
Roldan initially sent off midfielder Siani, drawing furious Cameroonian protests with Broos incensed on the sidelines, and even Germany boss Loew got involved.
The video referee then stepped in and amended the decision with Mabouka eventually handed his marching orders instead.
The dismissal rattled the Africans and Germany scored a minute later when Werner headed beyond Ondoa.
A fumble by Marc-Andre ter Stegen gave Cameroon a glimmer of hope on 78 minutes as Aboubakar's header flew through the German goalkeeper's fingers.
But Werner put the result beyond doubt when he fired home substitute Benjamin Henrichs' pass on 81 minutes.
Werner could have finished with a hat-trick as he drilled a late effort straight at Ondoa.