Sitnikov had his first international success at the 2016 Junior World Championships in Sofia . There he won the bronze medal with the relay. He started the World Cup for the first time in February 2017 in Dresden , finishing 19th over 500 m and 11th over 1500 m. In the 2017/18 season he won the silver medal with the relay at the 2018 European Championships in Dresden and at the 2018 Junior World Championships in Tomaszów Mazowiecki . At the highlight of the season, the 2018 Winter Olympics in Pyeongchang , he achieved 27th place over 1500 m. In March 2018, he finished seventh with the relay at the World Championships in Montreal . In the 2018/19 season he won in Turin with the relay and the mixed relay and also came in third place with the relay in Salt Lake City . At the European Championships in Dordrecht in 2019, he won the bronze medal with the relay and over 500 m. In the following season he got two wins with the relay and won four times the second and twice the third place with the relay. He was also third in Montreal and second in Nagoya over 500 m and thus achieved fifth place in the World Cup. At the 2020 European Championships in Debrecen , he finished ninth in the all-around event and won the gold medal with the relay.