As a curious thing, when you challenge her the first time, she says you'll receive as reward a "Heavy Sack of Gold". After defeating her, she gives you only 9 gold and 80 silver coins... until you check your mail, where you'll get a 3000g from her and a letter which starts with "I thought there was no way you could beat me..." ;)
A word of advice, every body always says "you can counter this pet type with this one", but the truth is use those you trained and you know well. Every time I listened other people's advice about what type is stronger against any other, I lose. Whenever I used the ones I trained and I knew what they were capable of, I won.
I defeated Aki with a team of my own, completely different from the recommended one at first try with no problem at all.