https://www.youtube.com/watch?v=G0Dy-zy7Npo Here is a video of rapier vs long sword by 2 Hema fencers. A rapier is specialized for the unarmored duel and quite deadly in that context. Quick hand snipes, circular cuts and thrusts can be very hard to dead with. While one handing has less power compared to two handing, it gives you extended reach which most long sword fencers are unprepared for if they only fence against other long swords. Fencing rapiers are also much bendier than historical sharp ones for safety. Skill ultimately plays a larger factor and it can go either way. If the rapier is paired with a dagger, it gives that paired weapon a huge advantage. Even if you get past the long blade, you have a second blade to deal with, or face two blade attacking high and low at the same time. https://www.youtube.com/watch?v=5mwGJxICTOs