When distance is locked in (you can’t really move in any direction to correct your course, whether because of your posture, or your opponents strikes) there is a sweet little trick from the Italian method. It’s a rapid change of attack direction mid attack, or even mid defense.
This can be either a fendente to sottano (downward strike to upward strike) or vise versa.
This video shows a fendente to sottano. I struck downward from my weak side (fendente reverso) then when my blade was low and passed the opponent, I turned the blade so my strong side faced upward, and did an upward cut from my strong side (sottano mandritto). I may have hit with my fendente but two things caused the sottano. One I didn’t think I hit hard enough that a judge would see it, second I had a threat here from my opponent and used the sottano to keep me defended. I had no time to move, and my blade was low.
This switcharoo must be fast and clean. Practice this combo slow and clean first, then work on getting faster and faster. Commit it to muscle memory and it becomes a powerful tool!