Career
Demyanenko was a late developer and only came to prominence in 2004 with a shock victory in the C-1 500m final at the European under-23 championships in Poznań, Poland. His time of under 1:50 was comparable with those recorded by the finalists at the Athens Olympics. In 2005 his coaches judged he was ready to take on the seniors but no one expected what was to follow.
The following month, at the 2005 Flatwater Racing World Championships at Zagreb, Croatia, he was entered in two events.
In the C-1 500m he came fourth. Then in the C-1 200m final he turned the tables on Opalev, winning the final in a time of 39.264 seconds.
After these successes Demyanenko began to concentrate on the C1 500m in preparation for the 2008 Summer Olympics, where there would be no 200m races. This time he finished in the silver medal position.
In both events he was beaten by Russia"s Nikolay Lipkin.