Belger won the bronze medal with the German relay team at the Junior World Championships in Liberec in 2013 and was tenth in the 5 km freestyle and seventh in the skiathlon . In December 2013 she made her debut in the World Cup at the Tour de Ski , where she missed the points in the first two stages and did not take part in the third section. At the 2014 Junior World Championships in Fiemme Valley , Belger finished ninth in the skiathlon, fifth over 5 km classic and fourth in the relay. Then she started in Oberwiesenthal for the first time in the Alpencup , where she placed fourth in the 10 km classically among the top five. In December 2014, at the fourth start, she achieved her first podium in the Alpine Cup with third place over 5 km classic in Hochfilzen . At the beginning of January 2015, Belger took part in the Tour de Ski again, but finished the race again after two stages without being able to score World Cup points. A week later she started at the Alpencup in Oberwiesenthal, where she won the 10 km classic race after 14th place in the sprint and seventh place in the 10 km freestyle. Belger then took part in the U23 World Championships in Almaty , where she finished 18th in the 10 km freestyle and eighth place in the skiathlon. Two weeks later she reached the classic podium again in second place over 10 km at the Alpine Cup in Campra . At the beginning of the 2015/16 season , Belger finished fourth in the Alpine Cup in Prémanon in the 10 km freestyle and won her second race in the series over 10 km classic. In the further course of the season she came third three times and second twice, winning the overall ranking of the Alpine Cup. At the U23 World Championships in 2016 in Râșnov , she finished seventh over 10 km classic and sixth over 10 km freestyle. At the beginning of the 2016/17 season, she scored her first World Cup points in Davos with 17th place in the 15 km freestyle. At the 2017 U23 World Championships in Soldier Hollow , she took eighth place in the skiathlon and over 10 km freestyle. In the Alpine Cup she achieved two second places and thus reached 12th place in the overall ranking. At the German cross-country skiing championships in Oberwiesenthal in 2017 , she finished second in the team sprint together with Monique Siegel . In the 2017/18 season she came third in the overall ranking of the Alpine Cup with a first and a third place. In the following season she won the pursuit of the Alpine Cup in La Brassus and came third in the mass start race over 20 km freestyle at the German cross-country skiing championships 2019 in Reit im Winkl and second place with the relay of WSC Erzgebirge Oberwiesenthal .