Piller took part for the first time in a major international event at the Junior World Championships in Schonach in the Black Forest in 2002 and was 35th in the mass start race over 15 kilometers, 45th in the sprint and 57th in the freestyle race over five kilometers. At the Junior World Championships in 2003 in Sollefteå , Sweden , she finished 37th in the mass start race over 15 kilometers and 38th in the sprint. At her last Junior World Championships in 2004 in Stryn , Norway , she was eighth in the freestyle race over five kilometers, 25th in the sprint and eighth with the Italian relay. She did not finish the mass start race over 15 kilometers. In January 2006 she ran her first World Cup race in Lago di Tesero , which she finished with 56th place in the 15 km mass start race. At the U23 World Championships 2007 in Tarvisio, she won bronze over 10 km freestyle. She got her first World Cup point in Rybinsk in the 2007/08 season with 30th place in the 15 km mass start race. From 2006 to 2012 she mainly competed in the cross-country alpine cup . She got five wins and won the overall standings in the 2006/07 season . In the Tour de Ski 2012/13 she reached 42nd place. In February 2013 in Davos she took seventh place in the 10 km freestyle, her best individual World Cup result to date. Her best results at the Nordic World Ski Championships 2013 in Val di Fiemme were eighth place in the relay and fifth place in the team sprint. Over ten kilometers in the free technique, she took 20th place. She finished the 2012/13 season in 66th place in the overall World Cup ranking and thus her best overall World Cup result to date. Her best placings at the 2014 Winter Olympics in Sochi were 16th in the skiathlon and eighth in the relay. The placements were later withdrawn because of doping. At the Italian cross-country skiing championships in 2014, she came second in the 30 km freestyle and 10 km classic. In the skiathlon she became Italian champion. At the Nordic World Ski Championships in 2015 in Falun , she achieved 40th place in the skiathlon, 13th place over 10 km freestyle and ninth place with the relay. Then she ended her career.
After her career, she was banned for the calendar years 2017 and 2018 because of the values in her blood passport. As a result, the placements from November 2013 to February 2015, including the results at the 2014 Winter Olympics, the 2014 Military World Ski Championships and the 2015 World Ski Championships, were retroactively revoked.
Italy
Oberstdorf
Medvode
Obertilliach
Monastery