Combine ingredients except pork in a large ziploc bag and shake to combine. Add pork to the bag. Shake to coat and massage the marinade into the meat. Place in the refrigerator for at least 30 minutes or unto 4 hours. (Any longer than 4 hours and the acid in the lemon will begin to “cook” the meat. If you need to marinate overnight, leave out the lemon and add it 30 minutes before cooking.).
Make the Chimichurri sauce:
Combine ingredients in a small bowl. Set aside until ready to serve.
Grill the tenderloin:
Pre-heat an outdoor grill to medium-high heat (about 500 degrees). Place the marinated pork on the grill and cook for about 20 minutes, turning occasionally to char all sides. Meat should register 145 on a meat thermometer at the thickest part of the meat. *Note: if meat is not fully cooked but charred all around, additional cooking time in a 400 degree oven may be required to reach desired internal temperature.
Transfer the pork to a plate and tent with foil. Allow to rest 5-10 minutes. Slice into 1-inch thick medallions and serve immediately, topped with chimichurri sauce.
The nutritional values are for the pork tenderloin only.