She held off a Sith ambush party including Darth Bandon, Darth Malak's Right Hand, essentially, who was notorious for beating and killing numerous Jedi in combat.
She held off Malak himself later, and later as a Sith she also fought Revan and his party on a DS nexus, but it's questionable how much effort they put into the fight.
As for who she's beaten - Revan early in his training and some random Dark Jedi, lol.