Remove the pork tenderloin from the package, rinse and pat dry.
In a small bowl, combine oil, mayo, salt, pepper, garlic powder, paprika, and Italian seasonings.
Add the pork and the marinade to a large bowl or plastic bag and mix to full coat the pork in the marinade.
Marinate the pork in the fridge for at least 30 minutes, up to 24 hours.
Preheat the oven to 400°F. Add the marinated pork tenderloin to a casserole dish. Pour water into the dish, around the pork.
Bake uncovered at 400°F for 20-25 minutes, until the pork is golden and internal temperature is 140°F. (It will finish cooking during the rest time at 145F.)
Remove from the oven and rest for 4-5 minutes before cutting. (Do not skip the resting step!)
Slice and add to a serving platter, top with freshly chopped greens, and pour with some gravy if desired.
Serve immediately with desired sides.