Note, business man who has lived a 100 years. I think he is lot more intelligent then She-Hulk who is more then half younger then Namor. Namor also an ruler of undersea nation that is very warrior-oriented, and members of royal families usually get the best training available. And he has fought every major marvel character since World War Two, so he is much more better then She-Hulk, who has been an superhero for about ten years and got week of training against Champion, plus he is faster. If he comes straight from water, he is as strong as the time he knocked out Hulk. And it was not even simple knockout, Hulk flew miles back to shore and reverted back to Banner.
Namor wins in experience, speed, skill, intelligence and fury. She-Hulk wins in strenght. They tie in durability. Plus Namor has the flight advantage. Namor wins.