The second he put his hands on you.....wham.....if you dont have a weapon, go for his eyes....scratch his eyes out.
Also go for his crotch.......drop something heavy on his gonads.
In a situation like this, one has to become a wild animal. You are in a fight for your very life. Fight dirty. A knee to the crotch or scratching with fingernails is good. Fingernails are particularly good as scratches will pickup the attackers DNA.
Also good is batting the attackers ears with your open hand. Ears are surprisingly sensitive. Jabbing your fingers into their windpipe is also effective.
Going for the windpipe........good one.
Cut off the guy’s breathing. That’ll make his stop attacking.