It's happened to me quite a lot of times. The first time I beat Emerald Weapon was using it as part of my strategy (of course, I can now beat him without it
); I remember using the old "use demi on
x, then use mini on
y, then have
y attack
x 23 times, then end the battle and use 3 potions on
x" trick quite a few times
Unfortunately, it didn't work very well on Ruby Weapon :'(