This battle is going to be centered around DF abilities n skills, with a tad bit of physical combat, where I believe decides who would win more often than not.
I vote Law.
Law has already shown he's figured out the Puppet lives of Hawkins, a big part of Hawkins combat power. While Hawkins aside from Sea prison nails, has not shown an inept or in depth understanding of Law's room ability.
Hawkins imo isnt a strong physical combat guy, but as a captain I would have to I imagine he's similar to Law, and definitely more physically capable than Smoker. Still I think Law's h2h combat would be better...
Law imo, takes out half of Hawkins lives quick, then Hawkin pressure's Law with his Tarot probability abilities, hurting law..Law does his bunch if Room skills and eventually kills Hawkins..