Alexander Ovechkin has proven he's "The Greatest One" ... at least at goal scoring that is -- 'cause he just passed Wayne Gretzky for the most goals scored in NHL history.
The Washington Capitals star broke the record mere moments ago in Long Island, New York ... scoring a second period goal against the Islanders.
Check out the clip ... Ovi slaps the puck right by All-Star goalie Ilya Sorokin for number 895 -- and the crowd goes wild jumping and screaming while Ovechkin slides on his belly across the ice like a penguin in celebration.