if you can parry and close with him a bit inside his point, he's dead. unless he has a parrying (main gauche) dagger on his off hand and you get TOO close. if you also have a left handed dagger, it turns into a nasty knife fight.
i got a good smack from my epee teacher in college when my practice opponent made a mistook and his blade was grabable with my left, so i did. i poked him with mine a few times while the instructor, a rather aged hungarian about 5 ft 2 in. tall and 80-something got into range and gave me a good one on the butt with his fencing sabre. it's apparently against the rules
so is half-swording.ah, well... (he apparently got jumped by a few thugs one night on the subway going home thru the bronx in NYC. bad move. he put three in the hospital with his cane, he was small but all muscle and fast when he wanted to be.)
one of my favourite series was 'sharpe', i recall in the 'waterloo' episode one british cavalry officer commenting on french lancers that 'once you get past the point it's like killing rabbits'.
a similar instance early in ww1 saw a rare engagement between a british cavalry unit with swords and a similar sized german lancer unit actually charged each other. the brits had little trouble doing the rabbit thing and the german force retreated. the brits tried to cut them off but ran into a farmer's barbed wire fence and had to halt. a foreboding of things to come. one, if not the last, f the few actual cavalry engagements before the trenches and concertina'd barbed wire stopped all that noble stuff.
ps. - re the extensible sword, i had a vision of a few rubber bands between the hilt and the guard, you could hold the guard in your right hand and pull back on the hilt with the left, aim & let go.
just don't miss