Ippo vs Aoki and Kimura
This is just after Ippo's first arc, when he narrowly beats Takeshi Sendou the first time.
Takamura, bored without anyone to fight, decides to spread some rumors that Ippo is full of himself after his wins, and was talking shit about being able to beat Aoki and Kimura at the same time. So the two confront Ippo, and while he's trying to figure out what's going on, Takamura escalates things until a sparring match is set up, with him as the ref.
1. Ippo vs Aoki
2. Vs Kimura
3 rounds each, all out, no rest between match's.