Lets look at the facts, one has been trained since childhood in her art with strict and rigorous methods. She's now a master. The other is fascinated with fighting and imitates a fighting style.
Sakura has learned the Hadou ken and Shoryuken. both are special powers.
fact is, one hit on a normal person will instantly K.O. them, Hitomi doesn't have any special defenses, she is just a human with fancy Karate moves.
Not hating on her.
That's moot. Hayate has special abilities aswell, Hitomi can go toe to toe. She's far from normal, a human who can knock back a man that outweighs her by 100+ lbs with a single strike. Makoto has no special powers either yet she dominates, this is no different. She may have learned those techniques but by no means has she developed them to their full potential.
Keep in kind Hitomi has beaten a guy who can knock out fucking dinosaurs, twice. A Tai Chi genius who can shatter boulders with a 1 inch palm press, and matched Ayane, a prodigy, a Hajin mon master. To say she would be beaten by a simple hadouken (undeveloped at that) is pretty far fetched.
The hadouken is an outward manifestation of ki, all marital artists know of it. To defend against such an attack one would have to focus their own ki and act accordingly. Hitomi has studied and perfected every move and technique in her art of karate-do, every move has a purpose. She's no slouch when it comes to fighting 1v1 battles.