The duel between Osetrov and Li ended in the first round.
At the end of the five-minute period, the athletes arranged an exchange of blows, as a result of which the Russian was on the ground and allowed the opponent to carry out a rear-naked choke.
Lee won his tenth career win.
He also has five defeats in his track record.
Osetrov's record is 8: 3: 1.
Earlier Bellator light heavyweight champion Vadim Nemkov expressed support for the legendary Russian fighter Fedor Emelianenko before the fight with American Timothy Johnson.