When Laurel was fighting that street thug last week, she “underestimated [her] opponent”, that was why she was injured. Laurel did not lose, Nyssa ended the fight before she could - there was no winner or loser between them, because the fight never finished. Who are we to say she wouldn’t have bounced back from the knife strike?
So yes, it is possible that she fights better against enemies that she does not underestimate. Like League members holding her best friends hostage.
She did much better in the second fight of that episode as well.
Didn’t Oliver say only a few episodes ago that it isn’t about strength, it’s about heart?