2010–11 season was marked with mixed relay podium in Pokljuka and World Championships. The first ever World Championships medal was won at 2011 Worlds in Khanty-Mansiysk, Russia, when Ukrainian men's rely team (Semenov together with Deryzemlya, Sednev and Bilanenko) unexpectedly won bronze. It was also Serhiy's debut at these competitions. At 2011 Winter Universiade he won two gold and one silver medal. Semenov also won a silver medal at 2012, one gold at 2013 and two silver medals at 2015 European championships.