European hopes of claiming a gold in the event at London 2012 ended when Ovtcharov fell to a 4-1 defeat.
Ovtcharov was the last man standing for the continent, which has not produced an individual Table Tennis medallist on the world's biggest stage since Jan-Ove Waldner took silver at Sydney 2000.
There is still a possibility Ovtcharov will end that run as he is to face the loser of Wang Hao's meeting with Chuang Chih-yuan for bronze.
Third is now his target after his unusual service failed to befuddle Zhang as it has the rest of his opponents.
Ovtcharov has developed his own serve - he crouches low and springs back up before either delivering a backhand loaded with spin or a standard forehand.
The first game today was competitive, with Ovtcharov matching his opponent impressively, only for Zhang to pull away and take it 11-8.
Zhang looked set to run away with things thereafter, winning the next 11-3 as his famous backhand began to find its range.
Ovtcharov showed great heart in the next, with his sliced backhand service, in particular, causing the favourite problems - so much so that the deficit was halved.
But Zhang had the answer and edged the fourth 11-9 before sealing his place in the Olympic final when Ovtcharov hit long in the next.