Ryu (Breath of Fire) is a very strong and capable swordsman. He has considerable power even before he uses any of his dragon modes and other abilities. Mariko has also grown very skilled over the years but ultimately she isn’t nearly powerful enough to stop Ryu. She doesn’t have his level of experience or the finishing blow type of moves like the dragon forms. That is what will hold her back here. Ryu (Breath of Fire) wins.