When my opponent takes the center position, playing in a corner is a strong strategic response. By placing my 'O' in the top-left corner (0,0), I'm setting up potential winning lines along the top row, the left column, and the main diagonal. This forces my opponent to respond to a potential threat while I develop multiple paths to victory. All corners would be equivalent due to symmetry in this situation, but I'll choose the top-left to establish my position.