That's right, at the moment, her sword technique can indeed be considered as taught by Lin Dong.
Previously, when Lin Dong was in the Capital City of the Dragon Country, besides giving her a Broken-Mirror Pill, he also guided her in sword technique when he saw her wielding a sword.
He taught her some sword techniques, such as the 'Nine Flying Sword Point Technique', Sword Drawing Technique, and whatnot.
And what she just used was the grandmaster-level sword technique 'Evil Moon Single Slash'.
Its power is not weak, as it can cleave through the Strong Protective Qi of an early-stage Half-Step Earth Realm martial artist with not-so-strong defensive power.
This Ming Hao, although possessing the strength of a Half-Step Earth Realm martial artist, is only at the early stage.
Moreover, this unruly young master usually lacks combat experience and is not good at defense.