Help!! Italian Horror Title question!!

This one's a challenge to all you film buffs out there...

About 8 years ago, while on a high school trip to Italy, two friends and I were watching TV late at night. A strange Italian (I believe) horror movie was on TV and we all reacted quite strongly to it despite the lack of gore in the scene we were watching. The scene involved a woman being chased around her house/apartment/bedroom (not sure which) by some murderer in a really weird outfit. The movie looked like it most likely came out in the 70's or 80's.

All I can really remember other than this was one moment when he's holding her down on a bed and spreads her legs in an attempt (which fails as I recall) to stab her "there" (!!) with a knife (I said it was strange!). We were all shocked.

Years later, I've seen almost every Argento and Fulci horror film...but I still have no idea what this movie was or who directed it!! Could it have been Fulci's New York Ripper (which I still haven't seen)? Or one of Argento's early Gialli (I've seen Bird with the Crystal Plummage, it definitely wasn't that one)? Or a work by another Italian director?

I won't be surprised if noone knows what this particular movie is (my own memory of it IS really sketchy), but perhaps someone here could point me to some other Italian horror/thriller directors (other than Fulci, Bava and Argento) so I can explore for myself.

Its maddening to know that there could be countless horror films in existence that haven't made it to America. Perhaps this is just one of countless "lost" films that I was lucky enough to see during my brief stay abroad. In any case, revisiting this lost artifact of my visit (it was the only thing on TV I actually remember from the trip...aside from Baywatch) would be neat.

Thanks for the help.