Vassiliev made his
World Cup debut in the
1998/99 season. His best individual finish is second in
Garmisch-Partenkirchen on
1 January 2001, and he has total of nine individual podiums and three team podiums as of January 2018. His best finish at the
Ski Jumping World Championships is fifth in the normal hill team competition in
Oberstdorf on
20 February 2005, while his best individual finish is seventh in the large hill competition in
Sapporo on
24 February 2007. In the
Ski Flying World Championships, his best finish is seventh in the team competitions in
2004 and
2006. In the
Winter Olympics, his best finish is eighth in the team competition and tenth in the individual normal hill competition in
Pragelato on
12 February 2006.
Near-world record On
15 February 2015 in
Vikersund, Vassiliev flew to a distance of but crashed hard onto near-flat ground. Despite not being an official
ski flying world record, this remains the furthest distance ever reached in a FIS-sanctioned ski flying competition as of March 2025.
Summer world record On 15 October 2016, Vassiliev jumped in
Sochi at the Russian National Championships, improving the five-year-old summer world record on a plastic surface. ==Doping scandal==