"Was the booster hammers the reason she won against Daigo?"
Most likely yes. In the latest WN chapter, we got to see Kano's latest status, and she essentially, she has really high Speed, HP and Strength (in this order), although she is still small, and even if she has more skills, Daigo was still slightly higher level and had experience.
But dual wielding Booster Hammers with no penalty because of her innate skill, that's just impossible for Daigo to defend against, which is why she could play pinball with him. Remove that and she can't overwhelm him psychologically.
But, and this is one of the changes in the manga that may make it feel more dramatic, but it also makes it feel stupidier.
Who taught them the strategies to fight against strong monsters? Narumi.
What are the best weapons to fight against skeletons? Blunt Weapons.
What was Kano using against them? Dagger/short sword.
Are those blunt weapons? No.
Why did she think that using her normal weapons would do good, and why didn't she rent and got Narumi to warn her.
Some of the changes the mangaka does can be nice to some extent, but he is missing all the base, and that's annoying.
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For those who don't read the novel.
Originally Narumi and Kano farm on the Blood Baron BEFORE the competition, their first fight against the Blood Baron was with Narumi trying to kill him on the transformation sequence, and telling Kano that if he can't kill him in time, they would leave. Since he fails, Kano throws a potion (expensive by then, since they hadn't started farming yet), which Narumi complains, since they would be in the red if they rely on those expensive potions for this.
After they get the 1st one, Furufuru asks them for more, and lends them the 2 Booster Hammers, which she uses on the big fight and for farming from there on.
So since this is not the first time they are farming Blood Barons (Narumi would have to be with them first), they should already be aware of the cost of the potion, and to use blunt weapons.