[4] He moved in to the German lightweight men's eight for the 2001 season and they finished in overall ninth place at the 2001 World Rowing Championships.

The Nations Cup in 2002 and 2003 were the then-equivalent of the U23 World Championships and Sauer was in the stern of German coxed fours which finished fifth in 2002 and took gold in 2003.

[4] At the first true World Rowing U23 Championships in Poznan in 2004 Sauer steered the German men's U23 eight to a gold medal win.

[4] Sauer stepped into the German senior squad in 2005 and took a coxed four to Japan for the 2005 World Rowing Championships where they placed third.

[4] At the 2012 Olympics in London, the favoured German eight won the gold medal with a crew consisting of Filip Adamski, Andreas Kuffner, Eric Johannesen, Maximilian Reinelt, Richard Schmidt, Lukas Müller, Florian Mennigen, Kristof Wilke and Sauer.

In Rio the German crew won their heat but in the final were again beaten by Great Britain with a 1.33 second margin.

[6] In 2017 Sauer, Malte Jakschik, Richard Schmidt, and stroke Hannes Ocik were the only members of the German Olympic eight who rowed on.