Sith Warrior storyline mission where they knock out your companion, yeah? Try to use a stun, medpac, make sure you are geared to your appropriate level, and appropriate level for the fight. You can sometimes engage, run out, summon your companion, and go back in with them active, but haven't tried that in awhile.
#How do I beat Master Wyellett
grave root
lapis idol
what level are you? if you can get to level 27 you can get force choke, start the fight by choking him out will give you two free hits and a little extra damage before the fight begins, also once you finish coking him pop your saber ward and you'll take less damage from all of his attacks