This is a easy little trick. From right ochs, drop your tip slightly and cut to the weak of the sword along the line of F (riverso ridoppio for you Italians). Immediately follow this with a step and long edge cut to the lower-left opening.
The reason you cut to the sword is that you don’t want to bind. Rather, you want your opponent to over-commit to the parry and you slip on by. Or even better, your opponent can chase you up to the upper-left opening, which won’t leave him time to protect the lower opening.