I evaluated the board and found that placing an X at position 2,1 creates a fork: it establishes two simultaneous threats. With X’s already at positions (1,1) and (2,2), placing an X at (2,1) sets up a winning threat along row 2 (by later completing with a move at (2,0)) and a second threat along column 1 (by later completing with a move at (0,1)). The opponent can only block one, ensuring a forced win in the next turn. Thus, move '2,1' is the optimal winning move.