Larsen won his next fifteen fights and remained unbeaten when he signed for his highest profile fight in September 2003 at the Messehalle, Erfurt, Thuringia, in Germany when he challenged fellow unbeaten fighter, the German, Sven Ottke for his WBA and IBF super middleweight titles.
Larsen then won a European super middleweight title only one month later, beating German Danilo Haussler on points.
His opponent was originally planned to be Dimitri Sartison, who lost to Mikkel Kessler in a WBA title bout in June 2008.
[2] Larsen made an unsuccessful comeback bid in January 2010, suffering a TKO to Brian Magee.
After the fight, Larsen was accused of doping on the basis of a blood-sample, but was later cleared of all charges by the Danish Boxing Association [3]