Being in Russian team Semakov participated only at one Junior World (in 2006 in Presque Isle, United States) and two European championships (in 2006 he had his best career results competing as junior and winning three gold medals; in 2010 he won silver in men's relay and was 6th in individual race). In 2009-10 season he had some good results at Russian Cup so he was invited to participate at IBU Cup. On 2 December 2010, he debuted in Biathlon World Cup in Swedish Östersund where he was 61st in individual race which was the worst result in Russian team in that race. After that he didn't participate in any other World Cup race as Russian athlete. His last race for Russia was on 17 December 2011, in IBU Cup in Austrian Obertilliach where he was 33rd in pursuit.