Bows and flint and steels are your best friends - making sure he takes damage at a distance can save your life.
If you must use a sword, go to the water. If you can get under him, he won't be able to hit you, even with forcefield, since the range doesn't come from the legs. I've beat a full iron forcefielder while in half leather doing that. Water is also helping for hitting him with arrows, running for a while to try to shake him off, or doing "easier" sword battles that you can easily keep track of your health/regen in.
If you get lucky, you might be able to run from him and have him chase you until you find somebody else. Make sure you approach this person carefully. You wanna make sure you keep running away, but this new target is closer to him, so he fights this "new target" since he's less work to get to. This might bring his health down quiet a bit, so you can go in for the kill while he's low. Make sure this "new target" doesn't attack you first as well. lol.
Finally, fun tip: If you don't know whether they have forcefield or not yet and you have better gear, don't try to spin around them while attacking them at first. Rush in and pay more attention to hitting them than having them miss. This makes sure you get about an equal amount of hits off on eachother, regardless of forcefield or not, meaning you'll win as long as you have better gear. Spinning around them just throws you off and makes you miss quiet a bit against forcefielders or anybody lucky enough to hit you, and can cost you a win.
