At the end of 11 rounds of the tournament, Demchenko scored 8.5 points.
Second place was taken by 16-year-old German Vincent Keimer, who also earned 8.5 points, but lost to the Russian in additional indicators.
The third was another Russian, 21-year-old Alexei Sarana (8.0).
According to the results of the European Championship, 23 best chess players will perform at the World Cup, which will be held in 2023.
From the Russians, this list includes Demchenko, Sarana and Mikhail Antipov.
Earlier, Artemiev beat Carlsen in the Aimchess US Rapid qualifier.