In the Battle of the Boxers of Makunouchi Ippo (Hajime no Ippo) vs. Takeda Ikki (History's Strongest Disciple Kenichi), Ippo has come out on top 13 to 6. Ippo is a massively powerful Featherweight boxer, capable of ending a match in a single blow or pummeling you into submission over several rounds. His never-say-die attitude has driven him to endure hellish training to become one of the world's greatest Featherweight fighters.
Takeda Ikki (pre-Yami), was a former pro who had to end his career because of an injury during a street fight. However, he subsequently recovers after meeting Kenichi's Master, Akisame and begins training again. Later, he finds a Master of "practical boxing," and begins a bit of his own hellish training.
Makunouchi gets the fight in terms of experience, as far as boxing is concerned. However, if the fight we a street fight, Takeda might win since, he has more experience in that realm. Therefore, we will assume this is a fight with boxing rules, in which case, Ippo has the advantage. It would probably be a long fight and Ippo would be in pretty bad shape if he won. Whatever the outcome, though, there is no doubt that the fight would end in a KO.
That's all for now! Until next time, good luck and train hard!