is a bigger creature with similar str stat automaticaly stronger?

I had a discussion with my dm about how to handle str stat on a creature of large size. Lets say i have an orc with str 20 and something big like a basilisk or something, and i try to beat it in some str check or “contest” the dm states something like ” You cant tell me that an orc is stronger than a much larger basilisk!”. Even though it doesnt make much sense wouldnt i be still stronger because my str stat simply is higher?