With the new sword(melee system) no only do you have to melee, but if you sword first you will naturally melee faster the next time. If the opponent's sword clash rate declines you will soon be swording when they are not. Making you the victor.
If you don't have the best internet in the world, another good thing to do would be to strafe when you sword and move in a circle around your opponent. Must easier if you're playing on boxer or bumper jumper.
If you're still having trouble winning sword battles try backing off as soon as your melee will connect. considering most people playing at high level swords just mash melee, if you back out it will be out of range. This would make them sword, miss and during the waiting time between melee'ing again you can lunge(r trigger) and sword them.