In 2006, Kostoglod and Kovalyov came fifth at the European Championships and sixth at the World Championships in the C-2 1000 m. For the C-2 500 m events however Kostoglod was partnered instead by Ulegin. Together they became both European and world champions, finishing over a second ahead of their nearest challengers, the German pairing of Nuck and Holtz, in both finals. Kostoglod won a silver in the C-2 500 m event with Ulegin at the 2008 Summer Olympics in Beijing.