Thoroughly clean the pork loin. Do not slice the meat but simply trim excess fat.
Combine banana ketchup, light soy sauce, oyster sauce, rice wine, brown sugar, sriracha, Sprite and season with black pepper.
Marinate the pork for 30 minutes.
Bring the pork mixture into a boil and simmer in low heat until pork is tender, roughly 40 - 45 minutes.
Remove pork and set aside.
Premix cornstarch and water. Slowly add the slurry into the sauce little by little until your sauce thickens to your desired consistency.
Baste the pork loin with the thickened sauce and grill in a 220 degrees Celsius preheated oven for 12 - 15 minutes until the sauce caramelized. Baste more sauce if desired.