Sergei Rumyantsev, 55, said he was riding his horse near a paddock in the Siberian forests about 35 miles from his home in Eselyakh when he was "suddenly, unexpectedly" attacked by the bear, The Independent (Britain) reported Friday.
"I had a rifle in my saddle but I didn't have time to get it out. I only had a knife at hand," Rumyantsev said.
He said he was able to stab the bear while his hunting dog bit the wild animal and held it back.
Rumyantsev said he was scared during the attack.
"Of course. You try meeting a bear and we'll see how you do," he said to News.ykt.ru. "I was attacked by a large bear, aggressive. I would say he was about 10 years old."