So now that people mentioned what skills to use I'm gonna mention a few other things.

Are you using Grit? Did your friend use grit? If no Grit then you might be able to beat it then.

Also keep in mind DRK's DPS will vary due to damage in com, proc low blows and MP gained from Blood price.

Another thing is did you friend use food or a POT?

Also what weapon your using? Your friend may be 3iLV lower but if he has a better weapon then 3 iLV diff is nothing.