Light and Misa both own Death Notes and have experience in the field. Of course Misa can’t fight too well, while Light knows hand to hand combat. Also Light could write her name down pretty fast. Misa has a history of cracking under pressure. She got kidnapped and couldn’t fight back. Also she cracked after being in prison for a week, while Light spent a much longer time there and didn’t crack. Misa loses this classic fight. Light wins.