Retiwych has been taking part in the Eastern Europe Cup since 2008 . He has taken eight wins so far and won the overall standings in the 2011/12 season (as of the end of the 2019/20 season). In February 2009 he won the gold medal in the sprint at the European Youth Olympic Winter Festival 2009 in Szczyrk . At the 2010 Junior World Championships in Hinterzarten , he won silver with the relay. He ran his first World Cup race in February 2011 in Rybinsk , which he finished with 14th place in the sprint and thus also got his first World Cup points. In March 2011, he achieved his first top ten finish in the World Cup with ninth place in the sprint in Lahti . At the 2011 Junior World Championships in Otepää , he won silver in the relay and bronze in the sprint. He finished the 2011/12 season in 43rd place in the overall World Cup ranking and 14th in the sprint ranking. In all six sprint races he competed in during the season, he got World Cup points. His best place to date in a World Cup race he achieved in February 2012 in Moscow and in March 2013 in Lahti with fifth place in the sprint. At the U23 World Championships 2012 in Erzurum , he won gold in the sprint. In the 2015/16 season, he came in six times in the World Cup, four times in the points. His best placement was fifth in the sprint in Planica . In the following season he reached points in all World Cup participations. In February 2017, he won his first World Cup victories in Pyeongchang in the sprint and team sprint together with Andrei Parfjonow and at the end of the season he achieved 32nd place in the overall World Cup and 11th place in the Sprint World Cup. At the Nordic World Ski Championships in Lahti in 2017 , he came in 15th place in the sprint. In the 2017/18 season he finished 72nd in the Ruka Triple , 41st in the Tour de Ski 2017/18 and 66th in the World Cup finals in Falun . In January 2018 he finished third in the team sprint with Andrei Krasnow at the World Cup in Dresden .
In the 2018/19 season, Retiwych took 55th place in the Lillehammer Triple and achieved six top ten placements, including second place in the sprint in Dresden , 25th place in the overall World Cup and seventh place in the Sprint World Cup. He was also third in the team sprint in Dresden together with Artjom Malzew . At the season highlight, the Nordic World Ski Championships 2019 in Seefeld in Tyrol , he won the bronze medal in the sprint and the silver medal together with Alexander Bolschunow in the team sprint. After finishing 60th in the Ruka Triple at the beginning of the following season, he achieved 44th place in the Tour de Ski 2019/20 and in Dresden together with Andrei Krasnow third place in the team sprint. He also finished 52nd on the ski tour and was eight times in the top ten in sprint races. He again finished seventh in the Sprint World Cup.